Well if i think about it my absolute favorite villain is and will always be Death Gun from SAO aka Red Eyed Xaxa or Zaza i dont know1.Illumi Zoldyck
2.Thanatos from Saint Seiya
3.Sosuke Aizen from Bleach
4.Orochimaru from Naruto
5.Starjun from Toriko
Well my list changes depending on my mood