Foster's name is a reference to fostering, or providing parental care to children.
Foster's design draws inspiration from the traditional image of Santa Claus as a jolly fat man clad in red and white.
Foster's concept and design have not changed since they were first proposed.
Foster is the origin of the term "Foster Confirmed" used by the developers. The term refers to when a design is so overwhelmingly popular that it is assumed that it will appear in the final game, despite the fact that it has not been officially confirmed yet.