40px-Terminal.png This article, UNSC Fenrir, was written by Lord Ookami. Please do not edit this fiction without the writer's permission.
UNSC Fenrir
Production information

Fenrir (Marathon variant)


Reyes-McLees Shipyards

Technical specifications

1785 meters (5856 feet)

Engine unit(s)
  • Primary fusion drives (4)
  • Secondary fusion drives (2)
Slipspace Drive

Advanced Shaw-Fujikawa Translight Engine

Power plant
  • Mark III Deuterium Fusion Reactor (4)
  • Advanced Fusion Reactor (2)
  • MITHRIL Polarized Armor System (2550-2552)
  • Mk III Energy Shield Generator (2553-Present)

250cm Titanium-A Battle Plate

Navigation system


  • 2 Heavy Magnetic Accelerator Cannons
  • 300 Oversized Archer Missile Pods
  • 50 mm Point Defense Guns
  • Shiva Nuclear Warheads
  • 24 C709 Longsword interceptors
  • 24 Pelicans dropships
  • 200 HEVs
  • 20 Warthogs
  • 10 Scorpion Tanks
  • 30 Lifepods
  • 500 Naval personnel
  • 2500 Marines

Human-Covenant war


Naval Engagement


United Nations Space Command

"There's a reason her AI's name means "Shield Breaker""
―Anonymous crew member

The UNSC Fenrir (CB-1736) is a Fenrir-class battlecruiser under the commanded of Captain Adrian Maxwell and home to the 122nd Naval Special Warfare Division.


Built in secret by ONI Section III, UNSC Fenrir is almost twice as long and twice as heavy as a standard Marathon-class cruiser, and was almost five time more costly to build. She features a prototype armor, cross-bracing and interstitial honeycombs, and two heavy MAC guns.


Construction of the Fenrir began in 2540 under Project: THOR, and was an attempt to create a more lethal and survivable class of warship. Unfortunately, her design proved too costly to warrant further production, and the project was canceled before Fenrir was completed. Listed as scrapped by ONI, she was in fact completed in 2547, and launched under the command of Captain Adrian Maxwell.

Notable Design Features

MITHRIL Polarized Armor System (MPAS)

  • Utilizes electromagnetically charged armor plates to disrupt EM fields surrounding Covenant plasma torpedoes and reduce damage to hull. This was eventually replaced by an energy shield generator, increasing her survivability.

Cross-bracing and Interstitial Honeycombs

  • Originally used in the Halcyon-class heavy cruisers, this method of construction, although expensive, greatly increases a ship's structural integrity.

Heavy Magnetic Accelerator Cannons (HMAC)

  • Number of cannons: 2
  • Ammunition: 2,000-ton Ferric-tungsten slugs
  • Muzzle velocity: 200,000 kilometers per second
  • Rate of fire: 4 rounds per charge (2 per gun)
  • Recharge time: 30 seconds
  • Each gun features extra capacitors and energy recyclers, enabling the Fenrir to fire two consecutive salvos from each gun on a single charge. Her six fusion reactors greatly improve recharge times.

Prototype Mark III Deuterium Fusion Reactors

  • Number of reactors: 4
  • These prototype reactors use a laser-induced optical slurry of ions chilled to near-absolute zero. This allows the reactors to be run at hotter temperatures, as the cooling system removes more heat as reactor output increases. These served as prototypes for reactors intended for UNSC Infinity.

Advanced Fusion Reactors

  • Number of reactors: 2
  • Based on a Forerunner design, these were built under the strictest of secrecy. Using a Mark III cooling system, they produce three times the energy, but occupy only a third of the space.

Artificial Gravity

  • Reverse-engineered from a Forerunner ship discovered on Valkyrie, the Fenrir can maintain a constant gravity throughout the ship. She also features several variable-gravity areas, including her drop deck and hangars.

Advanced Shaw-Fujikawa Translight Engine

  • Discovered on the planet Valkyrie, this Forerunner-designed engine was examined by ONI, and in early 2550, was installed on the Fenrir for tests. The results were surprising: the advanced engine allowed the Fenrir to make longer, faster, and more accurate Slipspace jumps than any ship in the fleets of the UNSC or the Covenant; it also makes her the only ship in the UNSC capable of making atmospheric jumps. Due to the complexities of the engine, however, it will be decades before it can be successfully reverse engineered.

Current Status

Officially, she is listed as scrapped before completion. In reality, she is home to the 122nd NAVSPECWAR Division, operating under ONI Section I. Her primary mission is to locate and secure information and technologies to help fight the Covenant. 122nd NAVSPECWAR includes a unit of Spartans designated Naval Special Warfare Development Group (NAVSPECWARDEVGRU), also known as SEALS Team VI.


  • The Fenrir is 1785 meters long, and was supposed to be the first of three ships: Fenrir, Jörmungandr, and Hel. 1+7+8+5 is 21, and 21 divided by 3 is 7