he was really intelligent, like an evil genius...

idk why i picked him... my instincts told me to because he almost killed reid

George and Frank is pretty tied for me,both was AWFUL,But i also really hate him from season 5 finale,he was scary as hell.

The reaper is a total creeper! (that rhymes :P) but Franks just ehh! He scares me!

Who's Frank again?

The reaper is totally unpredictable and took years to catch. I'd hate to come face to face with him.

I would say Frank only because of the wind chimes he left at Jane's house with all of the rib bones. I mean I guess some of the bones could have been animal remains but I think they determined they were all human. The Reaper was definitely bad but Frank killed over a hundred people and never got caught until finally the BAU was brought in. Those two are the worst to me. Tobias and Adam couldn't really help what they did.

He has been the only unsub that has caused someone to actually leave.

Tobias Hankel and Adam Jackson are not actually killers.... Charles Hankel (Tobias's dad) and Amanda Jackson were the actual killers. This is because Tobias and Adam did not make the decision to kill, but their bodies were "used" by another person inside them, to kill. In a way they are victims.