Terminator Genisys Ending: What Does It Really Mean?

Who Sent The Guardian Back?

The biggest unanswered question at the end of the film is who sent The Guardian (Pops' proper name) back in time. We've just about grasped what's going on with the T-1000, but it's a lot trickier when you get to Arnie. The mystery around the man/machine that programmed him is alluded to multiple times, but is left teasingly open (probably for a sequel - the writers say they do know who it is). As he's there to combat the T-1000, he must come from the original future (probably the same batch as the 1984 T-800, the feet of which are seen in the opening). That would rule out it being someone who only became key in the new timeline (like O'Brien, who would be an otherwise perfect fit), so the only logical candidates are either Skynet or a key member Resistance. However, the malleability of the timeline means it could feasibly come from elsewhere, so we really don't know. What is more open to discussion is Pops' long-term purpose. His mission is ostensibly to ensure the survival of Sarah Connor (he only attacks John because he already knows he's a robot) and never wavers from that, so he's either an out-and-out good guy, or being incredibly duplicitous. The answer to that is the key to who is calling the shots. At the moment there's simply not enough evidence to say what that is, but you can bet it'll be a key part of the sequel.