William Ennis

 was an employee at the Sierra Madre.

A locker called Ennis's Locker can be found and Ennis's Key which according to a computer log he "left his key on one of the consoles again ". In the same log he is referred to as "old man Ennis". The Locker also contains a note Toxic Samples which suggest that Ennis was one of the workers in the suits and may now be amoung the Ghost People.

Appearances
is only mentioned in the Fallout: New Vegas Add-on Dead Money.