Sarah Connor played by Jim.
Sarah Connor is the mother of John Connor.
Jim is a rather gung-ho roleplayer, interested in action, cool fight scenes, and lucrative spoils over careful consideration or puzzle solving. He frequently acts before he thinks, which includes fixating on his own strange explanations for setting details that the GM hasn't explained yet.
John Connor played by Ben.
John Connor is the future leader of the human resistance against the machines.
Ben is a thoughtful roleplayer who tries to think through the best course of action within his character concept and the setting. He enjoys coming up with clever ways to justify the success of his plans within the premises of the setting.
Miles Dyson played by Pete.
Miles Dyson is an electronic engineer with Cyberdyne Systems.
Pete is an old friend of Jim's. Jim invited him along to join in this new game. Pete designed a character to maximise all the skills he thought would come in most useful in a modern day cybernetic adventure, at the cost of having dependent kids and being fated to cause the downfall of human civilisation.
The T-1000 played by Sally.
The T-1000 is an advanced model Terminator made of liquid metal, sent back in time from the future to kill John Connor.
Sally is Ben's younger sister. Ben took her along to the game on the first evening when his parents couldn't get a babysitter for the night. The GM quickly gave her a character to play so she wouldn't get bored. She enjoys the make-believe aspect of the game, but has some trouble separating it from reality.
The Terminator played by Annie.
The Terminator is a cybernetic organism originally sent back in time from the future to kill John Connor.
Annie is an acquaintance of Ben's, who attends his drama classes. She was interested to come along and see what this "roleplaying games" thing was all about, after Ben described it to her as a sort of improvisational acting thing. She is dedicated to playing her character as a real, complex person with motivations inspired by a well-considered backstory.
Kyle Reese is a human resistance fighter sent back from the future to protect Sarah Connor from the first Terminator. His real concern is recovering the mystical Lost Orb of Phanastacoria, a powerful electronic device capable of deactivating SkyNet.
Dr Silberman is a criminal psychiatrist. He keeps an eye on people with insane stories about time travelling cyborgs and tries to keep everyone out of trouble, which seems to be a very difficult thing to do with so many time travelling cyborgs around.
Janelle is John's adoptive mother and guardian. John trusts her implicitly, but Sarah suspects her of some sort of nefarious plotting with the T-1000 to deceive John into a lethal trap. Who is right remains to be seen.
Mrs Dyson is Miles Dyson's wife. She is 38 years old, and uses her great wisdom and popularity to prevent her husband from accidentally bringing about nuclear amageddon. How exactly she gets away with this is a mystery.