Main Antagonists

Who do you guys consider the main antagonists of each season. I haven't watched the whole series in a while so I don't remember all of them but from what I do remember I say:

• Season 1-4: Dan Scott

• Season 5 and the first half of 6: Carrie. She was S5's biggest threat that I can remember

• Season 6 second half: I don't remember but wasn't it Victoria after Carrie was killed?

• Season 7 part 1: I say it was Rachel.

• Season 7B and Season 8A: Katie Ryan

I still haven't watched 8B and 9 yet lol :( I have them but I stopped watching the show a while ago (not like I quit it completely. I just stopped trying to catch up) and I have yet to start back. I need to soon though.