Just who that might be remains under debate.
Well, until now.
At least partially.
Earlier, Latino Review ran a story that stated Del Toro was going to play Khan in the sequel, according to a source.
However, HitFix went and asked the director, who responded with a very direct, "Not true."
So if Del Toro is not playing Khan, then who?
I'll throw this out there. How about the son of Khan?
A couple days ago we reported that Alice Eve was being brought on board to play a new character, and with that came news about another actor going to play an older villain/supporting character to Del Toro's villain.
Khan's son, Joachim, would work; it would fit both descriptions basically, and bear in mind it is an alternate Universe after all. Maybe Kirk kills Joachim's father this time around.
The as-of-yet unnamed Star Trek sequel is due in theaters May 17th, 2013 in 3D.