Darth Maul
Savage Opress has not been killed yet.
Darth Maul is Savage Opress' younger brother.
I think Savage Opress is perhaps a relative of Darth Maul ... I guess we're all going to have to wait and see.
I suppose this is more of an opinion question if you're asking about the characters' personalities, but power-wise, Darth Sidious is much stronger and far more cunning than Savage Opress.
The cheat code for Savage Opress is MELL07
Khameir opress is actually not his name. The previous answer submitted probablyvthough that because Savage Opress often refers to Maul as "brother" but this is not the case. Oppress means that they are both members of the nightbrothers. Maul's real name is Khameir Sarin.
That question is debatable. Personally, I can't tell since they're both extremely deadly and ruthless
As of January 30, 2012, he will return soon since the Season 4 finale is near and, according to Wookieepedia, the 4-part season finale is about the return of not only Darth Maul, but also Asajj Ventress and Savage Opress
Savage Opress has two brothers: Feral, seen in SW TCW 313 "Monster" who gets killed by Opress after the nightsisters transform Savage into a savage killer for Ventress' plot against Dooku, And the mysterious brother is none other than Darth Maul from "The Phantom Menace". Yes he did get sliced by Obi-Wan Kenobi during the Battle of Naboo, but apparently Maul survived and lived on in exile in the outer rim. Their was, I think, a non-canonical (I think, please correct me if you really know) story of Maul coming to attack Luke before Episode IV, and Owen Larrs apparently shot Maul in head after the Sith had a duel with Kenobi.
Darth Vader?
Darth Vader
Yes