D&D 5E "even" dualclassing

[Fanaelialae]

No, I can also ask at ENWorld if anyone else has already done this job for me

Sigh. If I got a dollar for every time somebody told me "you can always do it yourself" as if a) I didn't know that already and b) as if that "advice" were in any way, shape or form helpful... I would be a rich man today...

Perhaps I need to add this to my sig?

You are, of course, free to do whatever you please (within reason).

My point was that I doubt that such a thing could exist, because there are millions of possible permutations of abilities in the PHB alone.

To phrase it another way, I suspect what you are looking for is mathematically improbable to exist, and if it did I would be extremely sceptical of its accuracy due to the complexity involved. As such, likely the best you can hope for is to eyeball it on a case-by-case basis. You can, of course, forgo doing so yourself and crowdsource an answer on ENWorld, but that will still need to be on a case-by-case basis.

 

[Wulffolk]

In all seriousness, here is a half-baked ill-thought possible suggestion with no consideration for balance.

How about giving the character full access to the features of both classes, the average of the Hit Dice rounded up, and half the skills of each class. Just divide the XP in half to slow progression, similar to the way gestalt multi-classing was done in earlier editions. Any features provided by both classes are only gained once. For example, you only gain one +2 ASI instead of both when you hit 4th level. This would mean the character would be similar to classic multi-classing and be slightly behind the rest of the group in actual level.

 

[Mephista]

But... but... you do say hard rules work (perhaps not for everyone, but for enough)...?

For career changes "multi-class" specifically. Its rare enough (outside the fallen paladin, redeemed warlock archetypes, which have subclass-swap options) and varied enough that having suggestions is the best route to go. The other two kinds do need hard rules.

You mentioned the example that's actually the one I have in mind - the Paladin Warlock.

You want the character to meet the following minimum requirements, at the very least:
* Makes both his pact and oath no later than third character level, at the very latest
* Gets to pick at least a couple "signature" abilities, enough to satisfy both character-concept-wise and mechanically. For instance, if you feel a Ranger is no ranger unless you have Natural Explorer, you need to be able to get that rather quickly. Equally important, if a big reason you picked Paladin was for its Aura of Protection, you need to gain that at pretty much sixth level, or the entire endeavor loses much of its point (you might only be playing levels 1-10 after all).

Mmhm. I'd use the paladin class, combine oath and patron into one thing (you have an oath to your patron, basically), and go from there.
Probably I'd have a feature that swaps vanician half-caster to half-pact magic progression. And give access to limited Invocations. After that, its mostly spell list.

I would probably actually do a separate subclass for each warlock Patron. Or, more accurately, have them work like the Totem Barbarian, where you pick at the appropriate level.

I don't see any apparent or easy way to pick Warlock with a Paladin subclass, or a Paladin with a Warlock subclass...

Well, it would have to be a custom subclass in the first place. But I don't think its that difficult to do. The community has actually learned a fair amount about how to do subclass hybrids from experiences with the Favored Soul and Eldritch Knight.

Paladin/warlock especially is pretty easy, imho, because a lot of the fiddles on warlock are going to be set to "off" by default. Pal-locks are basically a variation on blade pacts by default, and have built in progression on blade techniques. That actually cuts down on a lot of things you need to translate over. Unless you're talking about making a tome-pal-lock, which is a different matter and slightly more complex. You can't even do blade-and-tome in warlock, so that's going to require a different approach.

Patrons give an ability at level 1, a defensive ability at 6 / 10, then an offensive ability at 14. Its easy enough to merge the defensive abilities into the paladin aura, and then translate the level 14 abilities into the paladin's 15th. Or into a smite-spell type thing.

Give me a list of abilities you want, and I could write up a subclass.

Being reformed is a completely different use-case. The whole idea is to be able to access both some Paladin abilities and some Warlock abilities at the same time

Yep. I was just explaining the career change multiclassing stuff, its actually not relevant to the discussion.