Shaun is voiced and modelled after British writer and presenter Danny Wallace. Shaun is a history expert and provides research and historical context to the Assassin characters in Assassin's Creed II, Brotherhood, Revelations and III - both verbally and through his entries in the Animus database. He also features in Assassin's Creed IV: Black Flag, but in more of a cameo role.
Unlike Desmond, Shaun was not born into the Assassin's Order. His independent research into conspiracy theories surrounding the power struggle between the Abstergo Industries and the Assassin Order brought him to the attention of both sides - leading him to be "rescued" and recruited by Rebecca and the Assassins before Abstergo were able to silence him.
Shaun is rather sarcastic and condescending towards his colleagues, having little patience for small talk or "dumb questions." He claims to enjoy his work from behind a desk, although he is seemingly frustrated by his inability to do too much field work.