FENRIS nuclear warhead

FENRIS Nuclear Warheads are retired low-yield bombs that the UNSC once used, they were replaced by the more powerful warheads mentioned elsewhere. However, recent actions had depleted the UNSC nuclear stockpile and these retired warheads, slated for conversion into peaceful purposes, were the only bombs they had left.

These warheads are first mentioned in Chapter One of Halo: Ghosts of Onyx where Blue Team has to infiltrate the rebel base, Camp New Hope on the planet Victoria, to recover these bombs. This mission took place in the year 2531, they will not be seen again until 2552 when Blue Team has to stop a group of Brutes from stealing 12 FENRIS warheads using the UNSC Centennial Orbital Elevator.

Spartan-051 (Kurt) uses the rest of the Fenris Nukes to prevent Fleet Master Voro from getting into the Mini Dyson Sphere on Onyx.