That depends on what you mean by psycho.  Sure Kodachi and B-ko

qualify,

but for Sailor Saturn I'd have to say Miyu (I love that laugh) or Tendo
Kasumi ("Oh my!")

Not stupid-psycho.  Kodachi and B-Ko instill no sense of fear in the
audience whatsoever.  Pity and amusement, yes....

I mean the real "this character has the power to destroy creation if she
wanted to" type of psycho.

Ifurita?

Umm ok I think I got the perfect character for ya.
Sharon Apple 
The perfect Character to Control, Create, and Destroy universes ^_-

Morisato Keiichi
Team Anime Member
http://ryokoshome.org/keiichi
Kei-Ohki@usa.net