FENRIS nuclear warhead

FENRIS Nuclear Warheads are retired low-yield thermonuclear devices that the UNSC once used. They were replaced by more powerful warheads. 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.

The casings of the warheads were super hardened. The reason for this was to contain the radiation and to hold the energy for a bit longer to boost the thermonuclear yield.

These warheads are first mentioned in Halo: Ghosts of Onyx, when Blue Team had to infiltrate the rebel base, Camp New Hope on the planet Victoria, to recover three bombs. . This mission took place in the year 2531. They will not be seen again until 2552, when Blue Team had to stop a group of Brutes from stealing 12 FENRIS warheads using the UNSC Centennial Orbital Elevator. It is assumed that the warheads were still used in the time between the above dates.

Spartan-051 (Kurt) used the rest of the FENRIS Nukes to prevent Fleet Master Voro and some 150 Elites and hunters from getting into the Micro Dyson Sphere on Onyx, where he said "Didn't you know?...Spartans never die."