Looking for a manga with an extremely intelligent/possibly crazy or psycho MC. Something like Tomodachi Game I guess. Any genre is fine but preferably it racks the brain or is somewhat horror or has mind games. Thank u.

Death Note is the classic example, of course.

One Outs, though he's not at all psychopathic, only mercenary. Don't be put off by the "sports" tag, it's pretty much all mind games.

Kakegurui and its spin-offs, for a rare smart-and-pyscho female MC.

Code Geass - Hangyaku no Lelouch - I recommend you to just watch the anime, since it's the original source.

Usogui
Rengoku Deadroll
Tajuujinkaku Tantei Psycho
MW
Funouhan
Goth
Lost + Brain
Perfect Classroom
Kuro no Tantei
Majin Tantei Nougami Neuro
Kuroshitsuji
Pandora Hearts
Yuukoku no Moriarty
Ajin
Gamble Fish
In Full Bloom (YON Jae-Won)
Kisshou Tennyo
Yamikin Ushijima-kun
Ad Astra - Scipio to Hannibal

Most of these MC's are more "ruthless and sociopathic" than "crazy and psychopathic," though. It's pretty tough to find a totally psycho genius in fiction, since the smarter characters tend to be more goal-oriented and so automatically become somewhat sane, at least by comparison.

A crazy and psychopathic example is Dead Tube, though you don't see much of the MC's smart and perceptive side until the current arc, I think (and even his psychopathic side takes time to surface).

Can't think of anything other posters haven't said for psycho (Unstoppable Siblings gets real crazy after a while), but just for intelligent MC there's also
Liar Game
Detective Xeno and the Seven Locked Murder Rooms

also there's a Smart Male Lead tag that would probably help you

Try happy sugar life
That one is kinda good but messed up at the same time
it is a fairly newer anime but it also has a manga

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