William O'Brien
From Halopedia, the Halo wiki
William O'Brien, also known as Bill O'Brien, is an American animator, artist and video game producer. He is also a current employee of Bungie. Born and raised in Boston, Massachusetts, USA, he attended art school and majored in animation. He specializes in both 2D and 3D animation.[1]
O'Brien joined Bungie in 2002. He was credited as one of the animators for Halo 2, Halo 3, and Halo 3: ODST.[2][3][4] In Halo Reach, the game he claimed to be proudest of any game he has ever worked on,[5] he worked as the animation lead.[6]
Trivia
O'Brien had an ODST don his name in the short, Another Day at the Beach. The ODST died in a Pelican crash during the events.