I think you mean Slade. He is basically Robin's nemesis. In the
episode "Aftershock Part II" (I think) Slade was melted and all the
titans thought he had died. But Robin felt he was alive. In an
episode after that (excuse me for forgetting the title of this one)
Robin sees that Slade is still alive and starts battling him. But
the other titans can't see Slade. Then they realize that Slade is
mentally tricking Robin. Robin cannot accept that fact that Slade
is dead (because Robin has been going crazy trying to find out who
Slade was ever since he met him) so his mind creates his own
version of Slade for him to battle. And Slade was winning. Robin
was on verge of death and the other titans had to save him. Later
in the series you find out that Slade really is alive and was
brought to life by Raven's evil father, Trigon.
Extra Info :)
Slade always wears a mask and in the cartoon you never see his
real face. In the comics I think his face is shown once. (Correct
me if I'm wrong on that part.)
Anyway, if you really do mean slave then I can't help you. I'm
afraid I don't have the answer to that. :( If that's really the
case though, I hope I expanded your knowledge on the character,
Slade.
