I forgot some…
Mokuren (Flame of Recca) Ugh, singlehandedly one of the msot despicable characters I've ever seen, and he JUST KEPT COMING BACK. That's why his death scene was so great... stupid weed.
Shishio (Kenshin) gasp! By the end of his fight, I was just sick of him. I mean, no one is THAT well prepared. I was SO pissed when Saito scored that hit on him, but Shishio was like "LOL I HAD A HIDDEN HEADGUARD."
that reminds me...
Ener really got on my nerves too. I mean, he was a good derranged villain, but he didn't seem appropriate for a dramatic arc like Skypiea, he seemed really childish. I was pretty pissed when he MANAGED TO RESTART HIS DAMN HEART. UGH.