King Runeard is an obvious fave of mine. Not so much because he as a character is that mindblowing, just the way he's portrayed and the way he plays into the story of Frozen is incredibly unique

Johan Liebert, hands down. Though other good mentions are of course Griffith, the Joker, the Batman Who Laughs, just to name a few.

Koba and The Dark Lord (Animator vs Animation)

Griffith and Frollo.

Lord Voldemort but the Joker and Daleks are honorable mentions

Patrick Bateman

Porky Minch easily

Although Dimentio and Bill Cipher are honorable mentions

Oh almost forgot Light Yagami

Gaunter O'Dimm