*Niko Bellic - confirmed protagonist. Has depression special ability. I sh*t you not
*Roman Bellic - Found in some code can be killed (optional)
*Luis - Found in some code. Dead.
*Eric - Lost biker. Old friend of Johnny.
*Gay Tony - Tony is Gay Tony. Kills Roman Bellic (optional)
*Bruce - Possible antagonist
*Johnny Klebitz - He is dead, but he appears during one of Eric's drug trips.
*Gunnut - Possibly the same from IV.
You need a pretty insensitive bullshit meter to even believe a single word from wherever this came from