Sebastian Monroe

Monroe is the IT guy of Owen's school, who helped the teenager to use an Animus to prove his late father's innocence of a crime he did not commit.

However due to Owen's discovery of clues about the location of the Trident of Eden, he became a person of interest for both the Assassins and the Templars. After Owen decided that the best course of action was to find the artifact first, Monroe decided to take Owen and his team of teenagers under his wing, as they searched through the simulations.

Reference

 * GameInformer: Assassin's Creed Is Getting A Young Adult Book Series Adaptation