Terminator: the Ouroboros Gambit

In this RPG (or story or whatever), Skynet's primary function is to control the human military in a time of crisis. One of its core functions in this regard is wargaming and strategy. The various conflicting timelines of the Terminator series are, in fact, Skynet running simulations using the most effective real-world model possible: real history.

The events of the various movies, the TV series, etc. are all wargame scenarios undertaken by Skynet itself to perfect the ultimate strategy.

For a twist, consider events as a sort of temporal chess between Skynet and John Connor: in the initial (filmed) history, he uses human agents, but following T2, he becomes aware (at a young age) of the possibility of a Terminator loyal to humans, and changes history accordingly.