+1
As wicked as Scar is, I always saw him as a little bit camp to be truly evil. Saying that, he does have a Iago-like quality to him in that everyone seems to trust him without question, heroes and villains.
Frollo has really got to be my first choice, but there's also:
Gaston, who starts off as so comical but by the end has become deranged with lust.
The older villains, like Malificent, who had no real motvie or reason, but were just born evil.
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We few, we happy few, we band of brothers;
For he to-day that sheds his blood with me
Shall be my brother;