Gersten

Gersten was a UNSC Marine stationed aboard the prowler UNSC Red Horse in 2552.

He and Sydney were Marine engineers subordinate technical officer Raj Singh.

The Mona Lisa
He was assigned to serve under Sergeant Zhao Heng Lopez when her squad, ordered by Commander Tobias Foucault, was sent to investigate the prisoner transport, the Mona Lisa, within the debris field of Installation 04, which was destroyed by John-117.