Sesshomaru (inuyasha)
Gendo Ikari(Neon genesis evagaleon)
Itachi Uchiha (Naruto)
Bo-Bobo(Bo-Bobo-Bobobo-Bobobo)
badass?? the most devilish character in anime...hehehe here's my list:
1. sawamura ryuuhei of hajime no ippo (a boxer - yet a very nasty guy outside the ring)
2. tobi of naruto (you'd see him funny or clumsy at first, but within him lies darkness)
3. enma ai of jigoku shoujo (well she really kicks ass of a bad guy, in a cursing way..hehehe)