Post a character with a Jekyll/Hyde-type personality

I've never watched Elfen Lied, but I hear the main character has a nice, sweet side (Nyu) and an evil, psychopathic side (Lucy).

Touko Fukawa may look like a depressing, quiet author... But when she sneezes...

Kisuke Urahara (Bleach)

he act funny, cheerful, idiot and playful outside but in the inside he is a very scary........deadly man......in bleach zanpakto's resemble their owners.........and kisuke's zanpakto is the most deadliest and fiercest zanpakto in the who soul society...........he only showed his true face once.......while training ichigo..........and it was a scary one......its meer like he is putting a funny mask on top, boven of his really scary face...e he he he h

Mia-Mia from Bamboo Blade. She can be sweet as honey but let's say she has some anger issues.

Agito/Akito (Air Gear)

Kagura from Fruits Basket comes to mind,sometimes she can really kind and timid but other times..the exact opposite-especially towards Kyo.