How do play a PC that's crazy, and simultaneously making him obnoxious and likeable?

This, he should be like Hopeman, not Genocider

It's simple really. When you do crazy shit make sure it never blows back on the party.

I played a Mentalist in Anima who literally was brain damaged from psychic damage he had sustained. He viewed the entire world on the basis of being an insect/member of a hivemind, even though he was the only one with any real psychic power. He referred to the party noble as "Queen", his bodyguard as "Soldier" and the mage as "Fire Ant".

In short, go unique, go obtuse, but don't let it sacrifice your usefulness to the actual game, or purposefully sabotage the party. It's an entirely different thing when a party member is doing stupid shit like trying to build a hive based on his own flawed logic, as opposed to trying to steal things or just talking like a gibbering imbecile.

The key is to use him as the butt of all jokes. If you don't steal the limelight all the time but instead set up jokes for other people, then it'll work.

In essence you also need a straight man.

I was thinking of playing a Malkavian as a really OCD guy, literally having to tread on manhole covers in a sequence and being forced by his compulsions to start again if he missteped. There's vampiric precedent; some folklore has them being compelled to count spilled seeds or salt in their path. What would be a good way to play this mechanically, and would it be too annoying?

I guess this is correct. Don't be LolSoRandumb, because that gets stale. Play by your own rules, your own set of morals. They may not make sense and it's better as long as they don't make sense, as long as they're at least somewhat consistent. This could result in somewhat hilarious situations where you could justify burning down an orphanage with "that orphan tugged my sleeve! She was clearly asking for it!"

Xellos wasn't crazy, just evil as shit.

Have lots of redeeming personal qualities that allow people to overlook the obnoxious bits.

Don't make the obnoxious bits personality traits that are obviously so like being rude or just doing random stuff. Right now I'm playing a huckster with some pathological delusions about the quality of his wares, but he's consistently friendly, gracious, even-tempered, and well-spoken. People like him, even when he sometimes gets these ideas for a product that lead to collateral damage and personal traumas for the people around him.

If you can get people saying "He means well" to excuse his behavior, you've made it.

And like other people are saying, there's a meta-element of needing to be at least a bit funny or personable to pull it off. No getting around that.

Genocider Sho is charming because she's such a straightforwards character.

She kills attractive men because that's her thing as a serial killer. Other than that, she's not really interested.

She's good natured in a twisted way and dumb as a box of rocks.

actual crazy people tend to be stressful and tiring if not blatantly scary rather than obnoxious, however it is possible to play it well if you learn what actual people with mental illnesses act like.

As for obnoxious AND likeable? You'd have to be funny probably, though depending on the game and your group, it might not be possible if they don't want a joke character.

>and dumb as a box of rocks
Is she?

But user Genocide Jack isn't a likable character. If I was in a party with her, or a similar character I'd kill her right off the bat. If you're going to play a crazy character that's obnoxious but likable go the Don Quixote route.

She was a likeable character in a VN, she would not be a likeable RPG character

Make way for best girl

I kinda like Genocider, even if she was moeshit.
Still not as bad as the goddamn bear.

I mean, the best of a pile of shit is something, I guess, but it's still not much of an accomplishment.

People call used to call me loud and obnoxous, and I still had plenty of friends. It probably has more to do with being witty than not.

not op here
i want to make a chaotic neutral or chaotic evil cleric of cthuhlu for pathfinder
i want to play as someone who spreads madness and insanity as a way to venerate my god, i wont be a good character but i dont want my team constantly waiting for an opportunity to kill me because im of a less than good alignment. long story short i want to be a chaotic cleric worshiping an evil god but i dont want to be "le edgy that guy"
any advice to roleplay that?

Do weird shit, like tilt all the paintings in the room to a specific angle, dance in the middle of the street and bark at anyone who joins you, do something fucking odd with a dead bandits body. The point is DONT be MALICIOUS about it.

>I want to make people insane
>without being evil
But you are

Just be entertaining and don't jeopardize the party's goals.

>do something fucking odd with a dead bandits body
i really like this idea,crazy but no one will try to stop me
thanks user
i get that i would focus on captured enemies or possibly people we save
i want to do the kind of evil my party will let me get away with, as opposed to, i rape the woman we just rescued or hurr durr i attack our quest giver
i get that but what type of mental illness should i use? what insanity would be entertaining.

Make the character be convinced of his/her likability, while taking down all doors in the building and replacing them with wet towels (for both more air and more privacy). Whenever you do something abnormal or obstructive, claim the other person's anger is the problem, and not the fact you decided to eat cat food standing over an open bin, while the rest of the party was busy preventing zombies from entering the cabin.

with great difficulty

>He referred to the party noble as "Queen", his bodyguard as "Soldier" and the mage as "Fire Ant".

Wait
youtube.com/watch?v=1HeWaNowogQ

the only likeable thing about genocider is the way she laughs

I'd be lying if I said that the party noble wasn't about half a step from being Megatron anyway.

This.
Crazy in service of the game, not just yourself.

Someone explain to me how having a split personality gives her a prehensile tongue.

Be "Jerry" Fucking "Jewell"

youtube.com/watch?v=4QdQZAZUlOg

everytime I had to interact with Tomo/Genocide Jack I wanted to kill her or myself.
Played the original and Despair Girls, I know what I'm about

dumb dog

Why is the Fairy Queen's tongue so long?

Like hitler

As a long time Malkavian player, I usually agree with the GM on triggers for the Malk's erratic behavior
Just describe the character's behavior as you imagine it for normal scenes, but try to stay productive and to participate, don't impose mechanical differences or hissy fits to the party
When your triggers come into play or when you or the GM deem that your character should have a particularly severe episode, inform the GM if they haven't picked up on it and they will decide whether or not to apply modificators and which to apply. The mental condition of your character isn't something they control (at least not completely for Malks) and so it should be partially out of your hands to deal with it
Please try and remember that first and foremost, PCs are supposed to be able to function in a group and to go along with a story, not paralyze everyone with their antics
Go and be a good malkavian, give a good name to the bloodline
Also it helps to have ''reasons'' for your madness, whether obscure and absurd as to throw people off balance or harshly grounded in reality to remind them that the kooky weirdo is every bit as dark as the others (sounds edgy, but WoD is all about edge-mastery)

I absolutely agree with you about functioning in a group, especially since I've never played before. What reasons might a Malkavian have, especially some that you've used?

best breeding sow you mean

High test girl.