I encourage you to try Everyone is John then.

Might be fun to add a check to it. Maybe something akin to a concentration check that they have to roll when they take damage to hold on to their connection to their patron. Failure means they flip.

That sounds like a blast

Wouldn’t that character get super nerfed fast? Even at an even split of class levels you’ll be half the class level of the rest of the party, with only hp/proficiency keeping up.

Main Character Syndrome

Sometimes it’s just about having fun.

French rpg bloodlust is famous for God Weapon having their own urges but not being able to indulge them without a human bearing the weapon.

Leading to the poor human getting some power based on what the weaponk let them do, while having a weapon begging them to indulge in violence, lust or any other awful sin.

Having a player having the weapon and another one the bearer open the road to pretty interesting roleplay

That and the changing every in-game hour. I’m rarely tracking time down to the hour, so it would either slow things down if they try to make any kind of scene out of it, or we’re just going to gloss over multiple changes, potentially making the whole thing moot. Then you get into a dungeon and someone might be locked out of “their” character for a large chunk of playtime.

Tracking who controlled for longer to determine the next level up sounds pretty tedious too, but I guess that would be the players’ problem to sort out, not the DM’s. I would worry that it may be an unforeseen detriment to their enjoyment though.

This sounds like a fun character. They even balance it out by not allowing the two classes to operate at the same time so it’s not OP.

It sounds like the character has the same total level as the rest of the party, but can only use features from half of those levels, so it’s going to be underpowered to the point of unplayability.

In 5e, if they took their first level as Paladin, they would gain Heavy Armor Proficiency. Having proficiency in heavy armor would allow a normal Lockadin to cast their Warlock spells in armor just fine. They also both heavily favor Charisma, and if the Warlock took Pact of the Blade or Hexblade, they wouldn’t even need strength for melee.

That’s a normal Paladin/Warlock though, with this weird hotseat play they want to do, their self-imposed rules might not let them even use the other class’ passive features, which could get awkward.

I actually did this once, only the good personality was a pacifist healer who was a liability in combat due to her aforementioned pacifism and her oath to help anyone who asks for it occasionally helping our enemies, and the evil personality was a sociopathic battle hungry sorcerer who just wants to cause as much mayhem as possible.

Mechanically speaking, the evil one surfaces in high stress situations (And even then, I have to fail a con save for it to take effect) and I automatically revert to the good one upon falling asleep or otherwise losing consciousness in some way. I ran all of this by my dm to make sure it wouldn’t screw over the party too much or be too powerful. It was my favorite character thus far.

Did your party feel the need to knock out your character from time to time?

At lower levels, this problem was quickly resolved by a simple sleep spell. By the time sleep fell off in terms of usefulness, character development had left my evil side with a sort of begrudging respect for my allies. (though I still didn’t care if they just so happened to be within splash damage range) By that point it was more of a mixed bag type of deal. The evil form was undeniably effective at nuking whatever threatened us, but couldn’t be trusted to handle delicate negotiations. The good side would outright refuse to help in battle, but was a superb utility party member. Because of how the mechanics worked, being evil was only a temporary problem that would resolve itself as soon as I take a rest, which obviously I would need to do to get my health and spell slots back. So to answer your question: yes at first, but eventually no.

So… Everyone is John? Dnd players keep reinventing the wheel and patting themselves in the back for it.