Count Nikolas Rokoff is a villain in the episode "Tarzan and the lost Treasure".
Rokoff is a very greedy and arrogant. He only cared for the treasure he was looking for. He was willing to Jane to get Tarzan to help him and only cared for himself. Rokoff is also an intellectual who is proud of being good at playing chess.
"Tarzan and the Lost Treasure"
Tarzan did not want to assist Rokoff but the man decided that he would kill Jane if he does not comply. Rokoff's battle with Rokoff continues for a while until Tarzan releases the last few leopards. After some time passed, the cave collapsed where Tarzan and the others managed to escape but it is unclear what had happen to Rokoff.