Five Deadly Venoms (1978)
I saw this as a kid and was entranced. I watched it again the other night and was surprised to see that it had aged pretty well.

The story is simple. The dying head of the Poison Clan has is worried that his former students are up to no good. He instructs his last student Yang, to go out into the world and discover the whereabouts of his five greatest students, all masters of kung fu, and determine if they are using their powers for good or evil. Yang knows a little of each of the other students' styles but can't hope to defeat any one of them on his own.
The Five Deadly Venoms are:

Toad-simple brutal power and completely impervious to most harm.
Snake-very quick style of striking with fingers and can fight on his back
Scorpion-powerful kicking attacks and uses poison
Lizard-Also very quick and can climb/fight from walls
Centipede-Also called One Thousand hands and uses a lightning fast combination of kicks and punches, flips and rolls.

Even the other students don't know who each person is and this winds up in a end of movie five man fight to the finish. Great stuff.
Typical dialogue:

Judge: On the night that the Yuens died, did you see this man?
Wan Fan: Yes.
Judge. All right. Well, he denies the crime. Use torture.