Warren Vidic is the Animus inventor in the modern-day story of the first Assassin's Creed.
Vidic is a scientist working for Abstergo Industries, the modern organization secretly controlled by the Templars. He oversees the Animus project and uses Desmond Miles to access genetic memories inherited from Desmond's Assassin ancestors.
The Animus is a fictional machine that lets a person relive ancestral memories rather than travel physically through time. In the first game, Vidic's research has a direct role in Abstergo's attempt to locate an important artifact through Desmond's memories.
William Miles is Desmond's father, Shaun Hastings is a later Assassin analyst, and Clay Kaczmarek is another Animus subject. They are important to the modern storyline but are not the scientist credited with inventing the machine.