Multiple Personalities?

[Paterack Attack]

I'm about to DM a campaign with alot of new people and they have already started thinking on their characters. One person in particular wants his character to be a paladin with multiple personalities. i personally love this idea and want to let him have. (i know he will have no problem role-playing it)

Personality #1: A clever manipulator and schemer
Personality #2: A thieving loner
Personality #3: A gung-ho rambo style character
Personality #4: A sad pessimist who feels the backlash of the other's actions

I've been wondering how to approach this. I'm thinking of him rolling individual mental stats for them all. He's already said that he wants a random essence to it, so i was thinking they would change with a role of the d3. i'm also thinking that each would need a paladin class variant (ex. paladin of tyranny, paladin of slaughter). i'm also thinking of giving him an immunity to insanity spells. What else should i include or change to try and let this flow as smooth as possible?

[Sintanan]

There's a creature I ran into in a Dungeon magazine once... it was three random personalities shoved together in one body, or something like that.

I do remember how the random personalities kicked in. During strenuous times, such as at the start of combat, when being struck, or during heated arguments, the creature rolls d3, and the personality rolled comes to the surface.

I'll dig around, because I believe it's a template, when I find it I'll edit this post.

EDIT
Found it. It's a "memelith". It's in Dungeon #117, so I don't think I can repost it here. I think I can get away with saying it's an inherited template that is the result of more than one soul being born into a body. Mechanically it gets some deflection armor, madness attack, immunities, the multiple-personality ability, some at-will cantrips (that trigger on their own), and minor stat adjustments. There's no LA, but there is a CR of +1.
Now, if this is too much info, I'll delete it. (Don't want to get GitP in trouble.)

[herrhauptmann]

Knew someone who chose a single axis of the alignment spectrum, and each day his character rolled a 1d3. Depending on what came up, his character would be either LG, LN, or LE. Another option at chargen could've been the options of LG, NG, CG.

To the OP, as cool as it sounds, I don't think someone with a class code of conduct should do something like this, not unless somehow all the personalities still kept to the code. Say a racist/misogynist (LG doesn't mean nice or tolerant...) for one, generic stick up the butt paladin, and an evangelist preacher type.
I mean, if getting mentally dominated or tricked into putting on the helmet of oposite alignment can make you need an atonement, so should your multiple personalities.

Either way, if you do that or not, make sure the character knows this before you start play.

[Paterack Attack]

Hhmm, what if it's the multiple personalities are derived from the inhabitance of four different souls in the same vessel. I don't think that would break the code seeing as the other personality's actions are in no way linked to the soul of the paladins of opposed alignment. it would also make for interesting story on down the line.

He could consider other classes, but he liked the idea of a wild card paladin

[Elric VIII]

Hhmm, what if it's the multiple personalities are derived from the inhabitance of four different souls in the same vessel. I don't think that would break the code seeing as the other personality's actions are in no way linked to the soul of the paladins of opposed alignment. it would also make for interesting story on down the line.

He could consider other classes, but he liked the idea of a wild card paladin

This seems like a rules-friendly way of handling this.

I just want to bring up the point of spell preparation. If you make his personalities become different Paladin variants, you could also have any alignment-based spells he has prepared also change. For example: LG paladin has Protection From Evil, if he becomes CG make it Protection From Law, if he becomes CE it is randomly Protection From Good or Law. basically have it become a function of which parts of his alignment are changing.