User blog comment:Dreyar/Everyone's Main Fanon Antagonist/@comment-4067913-20131013151732

Damn, didn't think this'd happen so fast. LET'S DIG IN.

Closest thing I can think of to a main antagonist is Eva Kielser in Fairy Tail: Vice. That's mainly due to the awful things she does to the main cast. She's a mad scientist, having created Automatons, 24 machines, as well as freely experimenting on others and doing whatever she wishes. Oh, and she has no magic, and her most dangerous trait is her intelligence and how she uses it.