Of gods, spheres, and magical chairs: A short examination of Spelljammer and 5th edition D&D Part 2

Note: Check out the apparently ill timed Part 1 of this short series of articles (WotC has a helm in the just released Waterdeep: Dungeon of the Mad Mage).

Divine Spellcasters Outside of Their Home Sphere. 

 

In my Spelljammer 101 post, I have a quick note that clerics are unable to communicate with their deity outside of a crystal sphere. Traditionally, this is mechanically reflected by not allowing clerics (priests, back then) to prepare their spells above 2nd level. So if they used a decently powered spell, they would be unable to recover it until they returned to a sphere where their deity had influence or managed to talk a similar, friendly deity to help them out.

I never got the chance to play in a 2nd edition AD&D Spelljammer game, but I can only assume this would be quite annoying.

There are some work-arounds:

• Spells that let you communicate with your deity
• The above mentioned getting help from a deity that is a friend of your deity's
• Worshiping an entire pantheon and hope at least one of them in that sphere
• Worshiping a deity that lives in the astral plane (and is therefore accessible in any sphere)
• Just be part of a non-deity religion, or worship ALL THE DEITIES!

There are two main problems with this mechanic in 5th edition:

1. It’s no fun to not get all your spells back, which could discourage people from playing clerics in Spelljammer games, especially if there will be a lot of travel between spheres.
2. Spell slots are based on your combined spellcaster level where multiclassing is concerned.

#1 is why it needs to be changed, #2 is why it won’t work without new, overcomplicated rules.


Is this a necessary part of spelljammer? I would say… Mostly. It’s a good way to mechanically explain why the deities of one setting aren’t the same ones in another setting, but the players end up with most of the burden of the current mechanics. What can we do? We change it, of course. The question is, how?


The first thing to look at is the way that spell slot progression has changed in 5e, which makes it so that either we create an elaborate method of calculating how many spell slots you get, subtracting some based on the cleric levels but not the others…


Or we just ignore spell slots.


Yup, ignore ‘em. You get just as many spell slots.


But classes still know/prepare spells based on the individual class levels, maybe we should focus on that instead. If you are outside of a sphere that your deity has influence in, you are unable to change prepared spells above… say, 3rd level. You can swap out spells of a higher level, but you can only swap in 3rd or lower.

If you go to another sphere with a begrudgingly friendly deity, maybe they would let you change out 4th or 5th level spells, and a very friendly deity might let you swap out 6th or 7th level spells. A deity that you complete a quest for would let you prepare 8th level spells, maybe even 9th, if the quest was of enough importance.

If you gain a level, and you would gain an additional prepared spell, your deity prepared for this eventuality and implanted the knowledge of the spell inside you, to awaken when the time was right.



There! I did it!


…but there is something else:



Spells aren’t the only thing that clerics get from their deity, they also have abilities like Channel Divinity and Divine Intervention. How do we make that fit into this?

Channel Divinity is also a paladin ability, paladins don’t even have to worship a deity, and trying to argue whether “justice” exists in a sphere doesn’t sound very fun, so I’ll probably leave that one alone.

But Divine Intervention. Your deity acting on the world on your behalf wouldn’t be possible in a sphere where they have no influence, let alone in the phlogiston! So maybe this should be it?


Let’s examine it:

• Most games only go to 10th level, where a cleric gets Divine Intervention. So this wouldn’t affect most players anyways. (I dislike this logic, so I would never stop at this)
• Deities have no ability to affect things outside of a sphere they have influence in, so this one makes sense for a cleric to not be able to use.
• If there is a similar deity that is friendly with yours, and they are willing, it might be possible to call upon them, especially if you perform a quest or task for them. If you are likely to spend a lot of time in a given sphere, this would probably be a good idea.

I think I will make a table that describes how the friendliness of a deity affects the Divine Intervention roll…



What do you think? Is my logic sound? Does this seem to fit 5th edition D&D? Is it staying true enough to Spelljammer?

Expect a third part of this series, where I will take feedback into consideration and write out more "official" rules that I will use in my Spelljammer game.

Of gods, spheres, and magical chairs: A short examination of Spelljammer and 5th edition D&D Part 1

Note: For a quick lesson on the basics of Spelljammer, check out my Spelljammer 101 post.


Way back in time, back before Wizards of the Coast owned D&D, it was owned by TSR. Due to management decisions, many strange things came about, best of which is Spelljammer.


I love Spelljammer, and though it has it’s problems… quite a few of them… the heart of it is of silly space adventures, swashbuckling action, and weird creatures not seen elsewhere in D&D.

…And it sadly hasn’t gotten any real support since its original line ended back in 2e.


So, of course, the fans have done their best to adapt it to newer editions, including 5th, but there is a problem. Two major ones in fact, in my opinion. Both of them stem from a conflict with 5th editions’ design philosophy: Spelljamming helms leave their user magicless until they can regain their spells, and divine casters can’t gain spells from their gods outside a sphere where their god has influence.


Let’s take a look at these two issues and consider how necessary they are to Spelljammer, and how they might be made to work in 5th edition. Starting with:

Helms taking all spells from their users

You are a powerful mage, the forces of the universe bend to your whim, you are ready to take to the stars and explore wildspace! You gleefully move to the spelljamming helm, curious to see how quickly you can master this new toy. Sitting down, preparing for this artifact’s power to flow through you… and then your magic is gone. All your spells have been drained from you, into the chair. How can you defend your ship if you get attacked? If you need to send a Message or escape quickly?

Basically, having to lose your magic just to pilot a ship kinda sucks. Sure, it FLIES, but you are just useless until you take a long rest, from the very start of the adventure!


How does this conflict with 5th edition?

Losing all your spells isn’t very fun. Having your powerhouse spellcaster reduced to a slightly tougher commoner isn’t very fun.

Is this a necessary part of Spelljammer? definitely not. Spelljammer does not need its helmspeople to be magicless. That said, it can add an interesting cost to piloting a spelljamming ship though, so should it stay? It certainly doesn’t have to stay in its current form, but let’s look at the options, as a sort of scale:

1. Leave it as it is. (The purist’s stance) Honestly, I’ve never played Spelljammer, not back in the day and I’ve only DM’d a 5e Spelljammer game which I’ve been putting off solidifying rules for. It’s possible that I’m overthinking it and it isn’t as big of a deal, but I don’t feel like that is true. The PCs could hire a spellcaster NPC to pilot for them, but that is also a trade off of losing all their spells or not getting to pilot the ship themselves. Might not be an issue for some people, but I wouldn’t want to impose that on someone that does see that as an issue.
2. Leave them with at-will abilities. A slight step away from the original “lose all spellcasting”, leaving the helmsperson with cantrips and other spells they would be able to cast at will would at least allow them to defend themselves and contribute to the adventure. Definitely preferable to option #1, but only a little.
3. All spell slots of highest level. It’s a bit jump from “all your spells” to “your most powerful spells”, and now that I think about it, it really does work. It’s a bit of a moot point for first or second level casters, but Spelljammer really seems to be more designed for fifth level and higher. And honestly, now that I’m writing this out, this one makes a lot of sense. It has a cost, that cost makes sense with how much the helm is powered, and it leaves the helmsperson enough magic to feel at least somewhat useful.
4. Helmsperson chooses a number of spell slots. Now we are letting the players make the decisions, how much are they willing to sacrifice to improve the ship’s maneuverability? This can also have an added limit to the number of spell slots, both to keep them from dumping all of them in and then feeling useless later and to reduce any decision paralysis. Limited to one spell slot would be simplest, but more might be more interesting.
5. Attunement by spellcasters only. Attunement is a wonderful mechanic, and with a slight tweak can work decently for helms: Multiple people can attune to it. Because nothing would be more annoying than stopping after each helmsperson’s shift to let the next one attune.
6. Attunement by anyone. Similar to the previous, but obviously, not limited to spellcasters. This is kinda where I feel that it begins to lose flavor. I suppose if it isn’t requiring the loss of spell slots, then it isn’t super dependent on spellcasters, and this allows non-spellcasters to use it, it might make it more fun for players who aren’t currently/don’t like playing spellcasters to try to pilot the ship.
7. Sit on helm. No attunement required, just need to put your butt in the chair. Why am I even putting this here? I don’t like it for several reasons, most of all because it feels lazy.

What option will I go with in my game? This has basically been my way of forcing myself to think about this and make a decision and I am definitely leaning towards #3 or #4. Honestly I really would like to test out #4 to see how the players react to it. 1 and 2 seem too harsh to be fun, and 5 to 7 lose a bit of the flavor in my opinion. I will probably write up rules for #4 and maybe #3 and post them at a future date.

Something else that I will need to address when I write those rules: The warlock problem, how to handle short rest spellcasters? I could either impose that it doesn’t last as long or isn’t as powerful… I will have to think about it.



Next time, I will examine the other big issue: Clerics being unable to regain their spells outside of a sphere where their deity has influence.

Spelljammer 101: The basics of Spelljammer

Ad astra per aspera

("To the stars through hardships")

— Latin proverb

Way back in 2nd edition of Dungeons and Dragons, the management philosophy was to crank out as many settings as possible to appeal to as large of an audience as possible. Since Sci-fi was popular at the time, the development team was forced to create a space setting.

And oh boy, did they.

Throwing in a mishmash of tropes, turning some on their head, and creating entirely new ones, Spelljammer was born.

Of course, the very management that demanded it also hated it, so each one of it’s supplements only got a single printing, leaving it to fade into obscurity. But no longer! Here, I intend to explain the basic ideas and rules of the Spelljammer setting, so that people can better understand the strange ways space travel works in D&D. With the exception of how physics work, most of these have a “usually” in them, as Spelljammer is designed to defy expectations.

Part 1: Spelljammer, spelljammers, spelljamming, and the Spelljammer.

First thing first: Spelljammer is not sci-fi. This is more of a pet peeve of mine than anything else. I’ve taken to describing it as “medieval space fantasy” because people have a hard time separating “in space” from science fiction. People are not in rockets or your typical spaceships/starships: They are on sailing ships. With sails, rigging, etc..

Sorry, I had to get that out of the way.

Sailing ships. Well, for the most part. There are several spelljamming ships that aren’t sailing ships, and most of them are certainly not NORMAL sailing ships that would be seen on our world. Spelljamming ships are usually wooden vehicles, sometimes with metal plating, almost always armed with canons, ballistae, catapults, and other weapons that fit in with D&D. This is getting kind of rambling, but point has been made, moving on.

The secret to how spelljamming ships fly is a magical device known as a helm. The helm is a chair or throne that is bolted to the floor on a ship, when a magic user touches the chair, their magic is used to power it, and they can cause the ship to rise into the air. In addition to the ability to fly a ship, the helm also gives it’s user awareness of the area around the ship, to help with maneuvering and allowing them to be safely below deck and not exposed on the deck of the ship.

Of special note, is that while “a spelljammer” can refer to the ship, one of the crew, or the magic user manning the helm, “the Spelljammer” is the name of the legendary living ship with a whole city on it, from which the setting gets its name.

Part 2: Everything you know about space is wrong.

Well, not everything. The space between planets is still an airless void, referred to as “wildspace”, and most things usually orbit around other things. The first things that someone would notice when leaving a planet’s atmosphere are air envelopes and the way gravity works.

Air envelopes

When a object or creature leaves the atmosphere, it takes with it a bubble of air relative to it’s size. A human sized creature takes with it enough air to last them anywhere from 40 minutes to 6 hours (I couldn’t tell you why it varies that much), and a large object, such as a ship, can take enough air for a crew to breath fresh air for months. After a time, the air envelope loses it’s freshness and becomes fouled, and people breathing fouled air take a penalty to checks. After the same amount of time to become fouled passes again, the air becomes poisonous and will eventually kill anyone who tries to breath it.

Coming into contact with the atmosphere of a planet with clean air will completely refresh a ship’s air envelope, or coming into contact with another ship’s envelope will cause an exchange of air, equalizing the freshness of both, according to the envelopes’ sizes.

Gravity in wildspace

After leaving a planet’s gravity, you would think that you would start floating off into space, right? That isn’t the case in Spelljammer, instead it follows a few rules:

1. Gravity’s range is determined by the size of the planet, creature, or object. A larger planet's gravity can extend out for miles, while a human's would only extend out a couple of feet.
2. Gravity is constant. There are always a few exceptions, but gravity is usually equal to our earth’s gravity whether you are on a planet (regardless of size), a moon, or a ship.
3. Down is subjective. On a planet or mostly spherical objects in space, down is towards the center. On a less spherical shaped object, like a ship, the gravity is usually divided by a plane. The top deck of a ship and usually the first deck are gravitationally aligned one direction, but further decks and the bottom of the ship are aligned the opposite direction. Once again, there are exceptions to this rule, a hallow moon could have you walking on the outside of it, then you enter a cave and you find the center of that moon is "up".
4. Gravity is determined by the largest object. Near a planet, that planet’s gravity takes over. Near a larger ship, that ship’s gravity takes over. This even applies to a person, who, if they were to drift away from their ship, could put objects or even smaller creatures into orbit around themselves.

Part 3: The wonders of wildspace

Once you have your bearings in wildspace, you would get a chance to look around at the wonders of your sphere, the immensely enormous sphere of an unknown substance that contains the sun, planets, asteroids, and everything else that exists in wildspace. Most spheres have a “primary”, or the body that is at the center that most things orbit around, which is most often a sun, but exceptions do exist.


The first thing you might notice about a sun, planet, moon, etc. is its shape. Spherical worlds are common, but far from the only shape that worlds can be. Some are coin shaped, some are geometric shapes, some are just weirdly amorphous. Just about any shape is possible (and likely exists somewhere).

In addition to it’s shape, planets, moons, and other bodies in wildspace are categorized by what element they are largely made of:

• Fire worlds are balls of flame, uninhabitable to most beings, and typically act as suns to illuminate everything in the sphere. Strangely, many are simply named “the Sun”.
• Earth worlds are largely made of earth, or at least have a decent amount of landmass on the surface. Many inhabited worlds are earth worlds, though not all are inhabitable.
• Water worlds are huge bodies of water sometimes with islands dotting the surface, and sometimes not. In colder spheres, water worlds can be entirely frozen.
• Air worlds are giant orbs of air, sometimes with floating islands inside. Unless the air is fouled, they are good places to refresh a ship’s air envelope.
• Living worlds are a type of world that is largely living matter, usually plants, and is very rare. This can range from a “relatively” small one that has grasped onto several moon sized worlds, or an enormous tree that fills it’s sphere and holds entire worlds in it’s branches.

There are also rare elemental mix worlds, but that’s a bit complicated for this guide, so maybe I will go into that if I make a more advanced guide in the future.

Finally, there are the stars. Which… are not stars as we know them. They could be glowing gems, portals to the plane of radiance, or they could simply be portals out of the sphere. Once again, anything you could think of could be the case somewhere.

Except for them being distant suns, billions of light years away. Because that would be weird.

Part 4: Beyond the crystal sphere

What do you do when the worlds of your sphere no longer interest you? When you need further adventure? When you need to REALLY get out of town?

You can head to another crystal sphere, that’s what.

As far as the furthest world is from the primary, and that far again, is the crystal sphere. It is mind mindbogglingly huge, to the point that if you go up and touch it, it will seem absolutely flat, despite being round. Most spheres have naturally occurring portals out of it, some are consistently open, others open and close on some schedule or randomly. Prepared travelers will have magic that allows them to temporarily open a portal themselves.

Once you make it through a portal, you will be bombarded with a brilliant display of a multicolored substance known as the phlogiston. It is what surrounds the spheres and flows between them, allowing travel. You can use these flows between the spheres to travel anywhere you desire. It can take months, and you may need to make stops at spheres along your way to freshen your air envelope and supplies.


Things to note about travel in the phlogiston:

1. The phlogiston mixes with the air envelope of the ship, and while it does not affect the air quality at all, it is extremely flammable and is very dangerous to anyone starting a fire or using fire magic.
2. The phlogiston cannot enter a sphere, no matter how hard you try.
3. While in the phlogiston, it is not possible to use any extraplanar magic- You are unable to summon creatures, use spells like Mordenkainen’s Magnificent Mansion, or items like bags of holding or portable holes. Similarly, clerics are unable to communicate with their deity.

Part 5: Other crystal spheres

After traveling through the phlogiston, you will eventually (hopefully) reach another crystal sphere. Once a portal is found or created, your ship can enter to explore the new worlds available to you. Things may be similar or completely different from your home sphere. In addition to unusual worlds, the rules may be different. Gun powder/smoke powder may not work, or certain races may feel an unwelcoming feeling of foreboding that manifests (mechanically) as a penalty to rolls, preventing them from having a major presence in a sphere.

In addition to the main three D&D settings (Realmspace, Greyspace, and Krynnspace), there are literally infinite spheres to explore, and mix that with planar travel and there is no end to the adventures that adventurers can go on. Some spheres aren’t easily traveled to (the spheres of the Eberron and Dark Sun settings), but a DM can always add those in their game if they want.



I hope that you enjoyed my guide, and that you learned a lot about the Spelljammer setting! In the near future, I plan to add more posts about it, including an examination of the setting’s special rules as they would fit into 5e, how I will codify those rules, a write up of the adventure I’ve made for my players (leading to an old module that I’m going to adapt for the next part of their journey), and more posts about the basics of Spelljammer (I’m thinking “Spelljammer 102: Peoples of wildspace”).


See you next time, space cowboy wizard.

Wildspace Magic - First Draft

Spells for Spelljammer adapted to 5e

 Spelljammer is... unusual. There are very few settings that take the usual high-magic fantasy  formula and put it into space, as space is typically seen as the purview of science fiction. As there was no precedent for High-Fantasy-In-Space (and other circumstances), the creators of Spelljammer were able to mold it as they saw fit.

This led to some... interesting components for the setting, but it is one that fascinates me to no end (which probably annoys my wife to no end).

While 5e has been almost entirely focused on the Forgotten Realms setting, with a short foray into Barovia, WotC has been hinting more and more that there might be expansions into new settings in the not-so-distant future. I fear that Spelljammer might be in the more distant future than some other settings (despite hints dropped into the adventures), so I figured that I would not be stepping on WotC's toes if I adapted Spelljammer spells to 5e.


This is the first draft of these spells, and I would really appreciate some feedback on wording, balance, and anything else that you think might be improved.




This is my first time embedding a PDF in my blog, so hopefully this looks alright.

Two big ideas to add to D&D 5e

I have been thinking about 5e for some time, and it has occurred to me that there are some things that could be implemented to benefit the D&D community and WotC alike.

Idea the first: Add a Legendary Player's Bundle to DnD Beyond

This one is pretty simple, and I'm kinda surprised that it has not already been implemented:  Make a trimmed down version of the Legendary Bundle (which is every piece of official content available on DnD Beyond at once, for 15% off, plus 15% off any future purchases) that only has player content. While the normal bundle comes with EVERYTHING, the player's version would only have content that is useful to players, making it much more appealing to players who don't DM.

Being generous, including all class options, race options, backgrounds, feats, and spells, the total value of player options comes to $100.90 (By my calculations, at time of writing this).

At 15% off, that would come to $85.77, which is much more reasonable than the $360.70 for the full Legendary Bundle, less than a quarter of the price! Since there are a lot more players than DMs, this would likely appeal to a wider audience than the Legendary Bundle ever could.

 The only things (that I can think of) that this would take to implement, are a few interface changes on the website, adding tags to all of the player content to mark them as a part of this bundle, and figuring out prices of future books with the player content discounted (or implement a system to do this automatically).

This idea originally also included all beasts that a druid could wildshape into and adventure specific familiars, but these seemed like something that could be cut for the sake of lowering the price a bit more (~$30).

Idea the second: Introduce setting guides to the DM's Guild

This idea would definitely take more effort to implement, but it would likely be extremely profitable for WotC.

Release a pair of PDFs (with print on demand options) every so often on DM's Guild (and probably DnD Beyond as well): 

This plan comes in three parts:

Part one is "The Player's Guide to [Setting]", with everything that someone from that setting would know: Major locations, people, creatures, culture, etc., maybe using condensed and/or edited versions of older setting guides, throw in some race and class options and everyone is happy. (and of course setting specific rules, such as for Spelljammer ships and travel)

The second part is "The Dungeon Master's Guide to [Setting]", which contains everything that the above player's guide has, plus further detail on everything. Where the pg has a note about some strange creature that the PCs might have heard of, this one has details about its behavior, habitat, diet, and of course, it's stat block (or at least what Monster Manual monster to use for it). It would also include quest ideas and potential dangers.

Beyond expanding upon details of the world, this book has a guide on how to run a game in that setting, how to capture the feel of it and express that to the players. How to run a pulp adventure in Eberron, get that post-apocalyptic feel in Dark Sun, portray the philosophies of the factions in Planescape, or the high-seas-in-space hi-jinks of Spelljammer.

Finally, the third and most important part: Open DM's Guild to submitted content for that setting.
Once the third part is done, all WotC has to do is sit back and watch the D&D community create multitudes of content for that setting. Adventures, more detailed location descriptions, more monsters, and a multitude of player options. A guide for creating content in the setting, and probably several Guild Adept adventures/supplements would be advisable, but not as required.

I feel that this idea is the less likely of the two, for several reasons:
1. It would take a lot more effort and possibly forming a whole new team just to tackle it (unless they want to at least partially hand certain settings over to Guild Adepts, like entrusting Eberron to Ruty Rutenberg and Satine Phoenix).
2. It could distract from whatever storyline the current adventure is focusing on, reducing sales of that adventure book and Adventurer's League adventures.
3. This idea has the possibility of getting rushed, just to get the content out there without sufficient playtesting or progressing the story of these worlds to keep them fresh for those who played them in past editions. This is a small thing, and might not bother people who just want their favorite setting adapted to 5e, but it could also cause those who are new to the setting to not be as interested.

Conclusion

Perhaps these are things that WotC has already considered, perhaps they even have them planned for some point in the future. I think they have a lot of potential, the first as a way to generate more (likely lasting) support from non-DMs in DnD Beyond, and the second as a way to open up the worlds of D&D to the community, and let their unlimited creativity add to the amazing possibilities that D&D allows us.

That and I want to see all the amazing spelljammer ships that the community can come up with.


I am curious to hear what people think of my ideas, so please leave a comment!

Weapons Not in the PHB That Monsters Use

Some time ago, I posted a small supplement to the DM's Guild called Monster Weapons!

It is an adaptation of all the weapons used by monsters and NPCs that aren't in the PHB, so that players can use them. It's good for games where you or your players want a few more options for their weapons, or so you don't have to panic if a player decides to pick up whatever wacky weapons their defeated foe may have been using.

Click here to check it out!

It is pay-what-you-want, which basically means it is free! (Unless you want to send a few bucks my way, I won't complain.)


Some of my favorites:

• Sword Cane
• Scythe
• Garrote
• Clawed Gauntlet
• Harpoon
• Sharktoothed and Spiked Weapons

Please check it out and feel free to leave a comment or send me some feedback.

If they ever post some new monsters with different non-PHB weapons, expect an update! (I'm looking at you, Mordenkainen's Tome of Foes!)

Reflavoring to get Avenger in 5e!

Wow, it has been a long time since I posted here! Almost 8 years! A new edition has come out, going back to more traditional D&D systems, rather than 4e's "POWERS FOR EVERYONE!" system. I love 5e and wish I got to play more often, but there are some things from 4e that I miss.

The one I miss most is the avenger class.

WotC tried to fit it into 5th edition.

The Paladin's Oath of Vengeance was their attempt to cram the avenger into 5e. It's better than nothing, but it was still built upon the base paladin class. It's a good option to play as, but it just doesn't FEEL like 4e's avenger.

And then Xanathar's Guide to Everything came out, I read through it, and I realized that it was finally possible (with some reflavoring) to have a proper avenger in 5e.


It's... Stay with me... The Hexblade Warlock.


Don't give me that look. It takes a bit of reflavoring, as I said, but it fits better than trying to paint a paladin as one. So, here we go:

Avenger in 5e!
 
Step one: Warlock core class 
Not everyone has played 4e, so lets start with a quick rundown on the avenger: Avengers are Divine Strikers. Divine meaning they are powered by the gods and Strikers being characters that focused on dealing damage. These descriptors came together to create what was something of a holy rogue, who would hunt and destroy their deity's enemies. Imagine a paladin, minus the armor, healing, and protection, leaving behind just the oaths and smites.

There is more to it than that, so maybe I will write another post later, to describe how avengers would fit in more with the 5e aesthetic. But for now, lets focus on the reflavoring!

• Patron - Your avenger serves a god, cause, or ideal, and receives power from that. 
• Pact Magic - Oath Magic, derived from your unwavering devotion to your cause. You are able to cast your magic using an arcane focus due to it sometimes being necessary to hide who you serve.
• Warlock spells - Avenger spells (obviously)
• Eldritch Invocations - Divine Gifts, what few things the hexblade doesn't provide to make a near perfect avenger, the invocations fill in a few.
• Pact Boons - Divine Boon, gifts bestowed upon the avenger to aid them in their task: A weapon, a guide/companion, or a book of secret magics.
• Mystic Arcanum - Mystic Invocations
• Eldritch Master - Divinely Favored

Step two: Hexblade abilities
Now we get into the interesting stuff that really makes it fit with avenger, in my opinion. The hexblade's curse makes a perfect Oath of Enmity,

• Hexblade's Curse - Oath of Enmity: Instead of cursing your foe, you swear an oath to destroy them, so strong are your words that your attacks become stronger, you become more likely to deal devastating blows, and even your wounds are healed when you fulfill your oath.
• Hex Warrior - Faith Warrior: You trained at a temple devoted to your god/cause/ideal to fight. As such you became proficient at battling in stronger armor and with more weapons. You also gain the ability to use more than just your physical abilities to attack.
• Accursed Specter - Accursed Specter: As you slay your foe, you bind its soul to temporary service of your deity/cause/ideal. Maybe with a cool catch phrase, "You serve my god now." (this ability doesn't really fit with the 4e avenger, but I think it is still really cool.)
• Armor of Hexes - Armor of the Oathbound: Those you have sworn an oath to destroy have a more difficult time hitting you. (I'm sure some of you would have expected this to be "Armor of Faith", but I felt that name fit better elsewhere.)
• Master of Hexes - Oath Master: When you defeat an enemy, instead of healing your wounds, you can instead swear a new oath of enmity on another foe.

Step three: Pact Boons/Divine Boons
 While it seems obvious that a warlock reflavored into an avenger would take Pact of the Blade, I think it would be silly to rule out the other options.

• Pact of the Chain - Divine Companion: Even the lone hunter can use a companion. With this Divine Boon, the avenger is gifted a magical companion to guide them along their path, assist them in battle, and give them a compatriot when nobody else understands them and their mission. While some would only want to use an imp or quasit with avengers serving evil gods, I like the idea of an avenger who used a questionable ritual to bind an enemy to their service, in this case it's already what they can do with Accursed Specter. If you don't want your avenger to have a fiendish companion, maybe they could just have an animal familiar or if they serve a dragon god, a psudodragon would be appropriate. 
• Pact of the Blade - Divine Weapon: Your avenger is granted the ability to summon a divine weapon. Honestly, this is what most avengers will choose, as it fits with the avenger's hunt and destroy mentality.
• Pact of the Tome - Divine Knowledge: You are granted a book of prayers that gives you the ability to cast magic that may have been lost or is forbidden to members of the church. This option would be good for the more studious or magic focused avenger, granting them more cantrips and ritual spells.

 
Step four: Warlock Invocations/Divine Gifts
Some of the Warlock Invocations are actually perfect for the avenger, mimicking abilities from the 4e version and filling out some of the abilities. I don't think that all of them need new names, but these are the ones that I felt would fit avenger best.

• Armor of shadows - Armor of Faith: Here is the one that fits better with the 4e avenger's Armor of Faith ability, especially since it can be gotten at a much earlier level and protects you from every attack, not just those from your oath of enmity target. It's not as versatile as the 4e version, as it only works on those with no armor, but I think it should work fine.
• Improved Pact Weapon - Improved Divine Weapon: Woo! A blessing to your attacks! It's not really that avengery, but it's one that is likely to be picked, so I thought I'd give it a rename.
• Thirsting Blade - Thirsting Blade: I honestly couldn't think of an alternate name for this one, but I don't really think it needs one.
• Eldritch Smite - Divine Smite: I kind of felt obligated to include this one on the list, though I might just be happy with the smite spells... Might want to have a slightly different name for this one if there is a paladin in the party though, maybe "Oath smite"?
• Maddening Hex - Shared Madness: I was pleasantly surprised to find that there is not one, but two 4e avenger powers that are similar to this invocation. Shared Madness's name even fit with it, so I had to add it in there. 
• One With Shadows -One With Shadows: I think everyone wants to be able to turn invisible, right?
• Relentless Hex - Censure of Pursuit: This is the ability that made things click to realize how well this would setup would work as an avenger, as it is very similar to one of the 4e avenger's core class options.
• Whispers of the Grave - Whispers of the Grave: I like the idea of the hunter that can ask questions of the dead to find his quarry. It's not for everyone, I suppose.
• Shroud of Shadow - Shroud of Shadow: See One With Shadows.
• Witch Sight - Divine Sight: Seeing true forms of creatures would definitely come in handy for someone who hunts monsters.

Step five: Spells
 Warlock spells have a distinct flavor to them, which don't necessarily fit with the flavor of the avenger. If you like you can rename and/or reflavor them, and maybe I'll do another post about it later if it seems like there is interest.


Wrap-up
I am excited to try this out, whenever I get a chance to actually play. I know it isn't a perfect match, especially with a focus on charisma instead of wisdom, but overall I think it is close enough. If you want to try it out, maybe surprise some of your fellow players, talk with your DM (make sure they know what's going on), and have fun with it!