We've been debating about Future Guy's identity for decades. We've been told mixed messages from the producers like Brannon Braga, who said that he was probably a Romulan and later said he was an old and bitter Jonathan Archer. It's still not clear what Archer had to gain from turning into Future Guy or what he was trying to prevent, or even how he'd live that long (and if Future Guy were Archer, wouldn't he already remember that his plans had failed? Or he'd have to be an Archer who lived a version of Enterprise that didn't have a Temporal Cold War) What's clear is that Future Guy is someone with a deep hatred of the Federation and wants to prevent its formation. Then it hit me. Wouldn't Krall, aka former MACO and Starfleet Captain Balthazar Edison, from the movie Star Trek Beyond fit this exactly? He's a former Starfleet officer who blames the Federation for him being stranded on Altamid, and hates how the Federation joins together with alien races that were hostile to humans instead of fighting them. Krall was killed in the Kelvin Timeline but we don't know his fate in the Prime Timeline. Perhaps he used his life extension tech till the 28th century, then after failing repeatedly to destroy the Federation, decides to use time projection tech to prevent the Federation from ever having been formed. As Krall/Edison was only a low ranking MACO at the time of Enterprise's Temporal Cold War, he may not have known much about it (or anything of it at all) to realize that his plans were already doomed to failure. Thoughts?