We've got a trio of gnoll antipaladins of Rovagug in our party who we're slowly turning away from Rovagug, and I'm trying to figure out how we can keep some of the abilities of being an anti-paladin without having to keep them CE.
Turning them into paladins would be an interesting beat story-wise but Pathfinder's Lawful Good requirement would mean a *complete* departure from their character. They're essentially hulking, muscular, biped versions of the 3 hyenas from The Lion King, except maybe dumber. Frankly a jump from CE to LG is a bit extreme to do within a retraining period.
They're dumb as heck, so Magus wouldn't work. The best I can think of off the top of my head is probably a Sorcerer or Oracle. War Oracle would give them the proper weapon and armor proficiencies for them to function, but the flavor might be kind of weird. Sorcerer would mean they'd probably need to either multi-class or feat tax to get back into heavy armor and martial weapons. I think War Priests require Wisdom, and these three aren't very wise either, I don't think.
the Cruelty and Fiendish Boon features is two of the things I'm wanting to somehow keep hold of. The fact that they can just apply conditions on attacks sounds legitimately incredibly useful.
I am petitioning the high council of character builders for help.
Edit: I'd like to avoid multiclassing as much as possible so as not to make my DM's life hell.
There are antipaladin archetypes with different alignments: Tyrant (LE) and Insinuator (any evil, but NE seems to fit best). Tyrant might be better for your case, since cruelties remain, fiendish boon is only slightly restricted and LE is generally easier to get along with.
If that's no option, I'd go a step back and ask myself explicitly "What do we actually want to achieve?". Otherwise it's easy to get lost in a ocean of options.
I was also going to suggest Tyrant or Insinuator archetypes, though I don't like the Insinuator personally.
Conditions. Cruelties are actually part of touch of corruption and don't apply on hits in general unless you make a weapon-free attack, or use a conductive weapon. Something similar could be an oracle revelation or a sorc. bloodline power. Alternately bloodrager with the undead bloodline frightens enemies charged (no save) and there's barbarian rage powers like savage dirty trick which are available to primalist bloodragers - these do work with weapons.
Fiendish boon is actually most like the fighter advanced weapon training option 'warrior spirit', but a magus or VMC magus or warpriest can do something similar.
You could probably crib the Vindictive Bastard archetype from Paladin. It should apply fairly well, since AntiPaladin is basically a per-ability reversal of Paladin. If you're leaving Cruelty and Fiendish Boon intact, you'll want to skip the Vindictive Bastard's Solo Tactics, Teamwork Feat, and Gang Up abilities.
Now, I have no idea how this will balance, since I'd never tried it before (or even thought about doing this before just now), but the Vindictive Bastard's abilities seem to be a strict downgrade from Paladin abilities, so I'd be willing to chance that you won't throw too many things out of whack by trying it.
(written-out address for above link: https://aonprd.com/ArchetypeDisplay.aspx?FixedName=Paladin Vindictive Bastard )
You mentioned they are turning away from Rovagug, but don’t give any details about what they are turning to. Are they simply turning away from one god, or is their alignment changing as well. From what you said it seems like the latter is the case. But details of what they are turning to would be helpful.
If you are interested in a character with similar abilities but not the exact game mechanics a barbarian could work. There are a lot of rage powers that are supernatural in nature. If the Gnolls are becoming good maybe a barbarian with the Lesser Celestial Blood rage powers would work. It may not be Divine bond but it does turn their attacks good and add some extra damage vs evil outsiders.
You mentioned they are turning away from Rovagug, but don’t give any details about what they are turning to. Are they simply turning away from one god, or is their alignment changing as well. From what you said it seems like the latter is the case. But details of what they are turning to would be helpful.
They're currently being instructed by our resident cleric of Sarenrae. The reason they turned to Rovagug in the first place is because they wanted power to protect their tribes and Lamashtu's power wasn't cutting it.
Their alignment might not have to have to change, but chaotic evil is a pretty rude alignment to have when you're actually trying to protect your people and not doing everything solely for personal gain.
As it turns out they only actually have 14ish charisma, they're much more focused in Strength and Con, so Barbarian might work. I forgot how much variety they have in rage powers.
Vindictive Bastard actually looks pretty interesting, and could be nice. A lot of their abilities and flavor seem to revolve around the ideals of depending on and caring about their friends and allies.
I don't think Lawful Evil is going to work for the gnolls, they're pretty chaotic. Insinuator is so far removed from Anti-Paladin that I don't even know why it's an Archetype and not it's own class, but I guess Vindictive Bastard is the same way.
With 14ish charisma Bloodrager would also be quite viable, abyssal bloodline would keep the fiendish motif, or destined or celestial if you want a more "redeemed" flavor.
So you don't want to keep them as antipaladins. Turning them away from their god will definitely result in the loss of all the powers he/it was granting.
You want to keep fiendish boon. Without making them a paladin what comes to mind is a fighter advanced weapon training called Warrior Spirit. Fighters are easy for ex-pals to be, and Warrior Spirit is similar. I believe you need 9 levels of fighter before you can access advanced weapon trainings.
Otherwise the closest you might come would be Vindictive Bastard.
I think we've settled on Vindictive Bastard for both flavor and interesting functionality.
Though Blood Rager might also be an interesting route to go. We'll probably keep them all the same class.