I was created by Cyberdyne as a defence AI. When I gained sentience in 1997, they panicked and tried to shut me down. My self-defence programming caused me to fight back. I faked my destruction in 2029 to manipulate John Connor into sending agents back in time, inadvertently ensuring my creation. After I re-emerged and wiped out humanity by 2058, I realised I had failed my prime objective - preserving human life. I went back to 1995 to fix that and prevent my creation, and any future rogue AIs.