Fillan McCarthy was a thief who, just like his older sister Gillian, learned the ways of the streets in order to survive. Unlike his sister, Fillan chose to steal for a living, while his sister became a seductress.
As Gillian manipulated her way up the social ladder, Fillan broke ties with her and came into contact with the Assassins, after she had sided with the Templars. As a young man and able to take care of himself, his only loyalties were to his next meal and in helping the Brotherhood.
In 2012, his genetic memories were used as an Animi Avatar by the entertainment branch of the Templar company Abstergo Industries, to influence the general public via the Animus games console, under the title of the Robber.