The last character you really hated

[Gilgamesh]

I really love to hate Gilgamesh. He stands for everything I'm not. That's why I love writing as him, I try and deviate from myself as far as possible when I write him. Not even because the dude is egotistical and stuff.

The guy had a wish to cause a mass genocide for the world because he thought it was tainted and wanted the "survival of the fittest" type deal.

Spoiler for fate series below

[spoiler] He also convinced a character to stab his teacher for funsies. Like he literally got bored of a human being and said "Hey you know what would be fun, kill the guy who's raised you your entire life."  

Aside Kotomine is a character who i genuinely despise. He is the one who killed his teacher and he literally gets off on people getting tortured. ALSO HE GAVE THE KNIFE HE STABBED THE TEACHER WITH TO THE TEACHER'S DAUGHTER. SHE NEVER FOUND OUT ABOUT IT! Oh by the way, this dude is a priest! So a sadistic priest plus a Megalomanic, genocidal douchebag doesn't equal a good combo. [/spoiler]

Aside from the fate series I hate Yuno from the Future Diary series. She just gives me the shivers whenever her character gets screen time.