Post a sadistic animê character.

Okita Sougo is like... duh... the... errr... Prince of All Sadists, in Gintama~!! ^.^

Alois Trancy

Mariko Kurama from Elfen Lied comes to mind,she thinks of killing as a game.

Johan Liebert from Monster.

Light from Death Note.

Junko Enoshima (from the video game Dangan Ronpa, soon-to-be-an-anime) is... she's kinda got a fetish or something ouo;;;

~~~trying not to delve too deep into spoilers~~~
Junko has a thing for seeing people in pain and suffering to the point that when people consider killing her, she finds it attractive...

Ladd Russo - Baccano!

Millions Knives is a bit on the sadistic side if I'm not mistaken~ Though it's been awhile since I've last seen Trigun.

I know Sougo Okita has been posted already but he is just too sadistic that I have to post him again XD

Shouko-chan from Baka to Test to Shokanjuu can act a little sadistic at times..especially around Yuji-kun.

Too obvious =___=
Kagerou Shoukiin
The very definition of Sadistic...HE IS FREAKING OBSESSED WITH S&M STUFF DX

As described por Teito, "Sadistic slave master"
XD

Castor from 07-Ghost.

kurotsuchi mayuri (bleach)

the best sadistic character i know..............

Mio Isurugi (MM!)
Both a sadist and a masochist in the anime, which is actually really sick with all kind of weird people

Kousuke Kira

Aria from Akame Ga Kill!

Esdeath, Akame ga kill