http://en.wikipedia.org/wiki/Colonel_Phillip_Green IMO the evidence is mounting up. He says he's "returned." Cumberbatch mentions that his character is neither good or evil. "He is a complicated character not to be judged by white-or-black, or good-or-evil. His character is also on a quest to destroy Starfleet specifically and take down the organization from the inside. This sounds very similar to Paxton (Peter Weller) in Enterprise who was a disciple of Colonel Green. Coincidentally, Peter Weller is in this film. Green was a leader of a major faction during the World War III; the group's actions directly led to 37 million deaths. The Enterprise episode Demons reveals that after the war, Green killed hundreds of thousands of victims of radiation poisoning in order to prevent their future mutant offspring from contaminating the human genome. Despite Green's claims that the operation was "humanitarian," this eugenicist action was labeled as genocidal by future historians. Green's ultimate fate still remains unknown.