Eric Tanner

The youngest son of the Tanner family, Eric grew up never really knowing of the existence of Gordon Shumway aka ALF, who had left the family due to the government taking the alien shortly after his birth. However before that, ALF had 'mind-melded' with the newborn to better understand his language and communicate. This had given Eric mental transmissions from New Melmac and without ALF there to help him, everyone eventually believed Eric to be insane and had him committed at 12-years-old.

When he was 18, he was to be released to his older brother Brian's care, but knowing Brian had become engaged, Eric didn't want to interfere with his upcoming wedded life and took off on his own, unwittingly implicating himself in the kidnapping of Brian's fiance. With John Connor's help, Brian and his fiance were reunited and Eric had been invited to live with his brother.

Shortly after the wedding, Eric became convinced he was the third wheel in his brother's life and because he'd proven he was good with tech, John Connor took him on as a partner to help hunt down Terminators to destroy the final T-850 and help build a time portal so that John could make sure Skynet was done for keeps.

After young Kyle Reese was blinded, John started leaving his father in the care of Eric when he went out on missions, leaving his training to Eric, who became attached to the boy and seeing him as a little brother.