Well Chang Shan of course
But then slightly above him was silver fox. My 2 favorite parts of secret rivals is when he puts on the kicking display where he just starts firing offroundhouse kicks like a machine gun and then when he calls Joh Liu out and goes down to meet him. He proceeds to do 2 huge leaps without breakign a stride. You have to see it to knwo what I am saying. Silver fox is the definition of badass.
I always liked Bolo to, though he was majorly underused. Image of Bruce Lee and the Fists, the Kicks, and the evils are really the only 2 that stand out for me.
And the thing that stood out for me in particular in Avenging Eagle was how he kept moving to the back of the mansion in the final fight, then a guy came and brang a box and set it by Ku Feng. Finally once everybody is dead, he finally opens up the box and we see these huge iron claws. The build up was just incredible. So that is the one thing that stood out for me out of 100's of great parts in Avenging Eagle.
Also some more would be Yen Shi-Kwan not really as a villian but more of Jet's opponent in Once Upon a Time In China.
Jason Pai Paio as the evil 9th prince with the iron fingers in Shaolin Prince.
Too many to name but you really don't get any more cool than Lo Lieh as Pai Mei.
"For someone who's a Shaolin monk, your kung fu's really lousy!"
"What, you're dead? You die easy!"
"Hold on now. I said I would forget your doings, but I didn't promise to spare your life. Take his head."
“I don’t usually smoke this brand, but I’ll do it for you.”
"When all this is over, Tan Hai Chi, I will kick your head off and put it on my brother's grave!
"I regard hardships as part of my training. I don't need to relax."