Othello。

[MangaDex]

 

[Purplelibraryguy]

Oh, hey, an old favourite! Yeah, I'm sure people will say "But it's not an accurate portrayal of mental illness yada yada yada". Whatever. Her alter ego kicks ass and is funny, the emotional story is good, pacing is good, lots of stuff is good.

 

[funyurinpa]

One of the first manga I ever owned!
Doesn't hold up quite as well as I remember, but is still plenty fun to read!