Production information
Manufacturer Defiance Industries[1]
Production Year 3063[2]
Model FNR-5[1]
Class Assault
Cost 11,470,000 C-bills
Technical specifications
'Mech type Inner Sphere BattleMech
Mass 100 tons
Chassis Foundation Type 220
Armor Durallex Special Heavy V2 [with CASE]
Engine Vlar 300
Communications System Angst Discom with Guardian ECM Suite
Targeting Tracking System Angst Accuracy
Heat Sinks 10 double
Speed 54 km/h
BV (1.0) 2,412[3]
BV (2.0) 2,636[1][4]


The Fafnir can be considered Defiance Industries of Hesperus' flagship BattleMech. (Originally the Defiance was intended to be that flagship 'Mech, but its actions tainted its reputation[5] so it was overshadowed in this role by the Fafnir).

The Fafnir is built on a lightweight Foundation Type 220 Endo Steel chassis that is capable of supporting the Fafnir's massive weapons payload and armor while weighing half as much as a standard chassis. The slow assault design serves as a platform for the pair of "Thor's Hammers" Heavy Gauss Rifles. To power this massive 'Mech, a Vlar 300 fusion engine gives the Fafnir a top speed of 54 km/h. The Fafnir is protected by nineteen and a half tons of Durallex Special Heavy V2 armor, giving it almost as much armor as the entire mass of some light 'Mechs. The Fafnir has CASE in both of its side torsos to protect it from secondary damage if one of the heavy Gauss rifles are damaged. Finally, for protection from enemy electronic warfare systems, the Fafnir has a Guardian ECM Suite.

Weapons and Equipment[edit]

Based on the heaviest chassis available, the Fafnir sports two of what was the Lyran Alliance's newest weapon in the early 3060s, the Heavy Gauss Rifle. The largest non-artillery weapon in existence, the Hammerfists can deal an immense amount of damage very quickly. Four tons of ammunition for each keep the weapons in good supply. The Fafnir cannot operate far from supply lines, however, as it only has two ER Medium Lasers and a Medium Pulse Laser as backup.


  • FNR-5B 
    A lack of Thor's Hammers during the FedCom Civil War forced engineers to come up with a field modification that could be useful without the Heavy Gauss Rifles. The solution was to replace them with paired standard Gauss rifles, ER Medium Lasers, and an ER Large Laser. The added energy weapons reduce the 5B's ammo dependency compared to the original, but even with extra heat sinks installed it can still run quite hot so MechWarriors must be mindful of their heat levels.[1] BV (1.0) = 2,230[6], BV (2.0) = 2,625[7]
  • FNR-5X 
    This variant makes use of a pair of massive experimental Improved Heavy Gauss Rifles, and removes the pulse laser to provide six tons of ammunition for the two guns. The ER Medium Lasers are left untouched. These models were used by the Skye Guards during the Coalition attack on Terra.[9] BV (2.0) = 2,610[10]

Custom Variants[edit]

  • FNR-4A Fafnir Peter 
    This was a salvaged command 'Mech piloted by Archon Peter Steiner-Davion during the occupation of Tharkad from 3067 to early 3072. This customization removes the left torso Heavy Gauss Rifle, half the ammo for the HGRs, the left torso CASE, and the ER Medium Lasers. It has been fitted with ten Rocket Launcher 10s. Also in the left torso are two Extended Range Large Lasers. In each of the arms and in the head, a Medium Pulse Laser been added. It makes use of a Compact Gyro, making room for one of the ten launchers, a Guardian ECM Suite, and a C3 slave computer.[12] BV (2.0) = 2,458

Apocryphal Variants[edit]

Apocryphal Content Starts

The information after this notice comes from apocryphal sources; the canonicity of such information is uncertain.
Please view the reference page for information regarding their canonicity.

These variants were introduced in MechWarrior Online, and thus far have not appeared in any canonical media.

  • FNR-5E
    The first PGI invented variant, the 5E is more focused on Missile and Ballistic weapons, the arms are affixed with a pair of LRM 5 and LRM 10 while in each torso carries an Ultra Autocannon/20, making this 'Mech a deadly adversary at both short and long range. Lacking any energy weaponry, the 5E carries four tons of Ultra autocannon rounds and three tons of LRM missiles.[13]
  • FNR-6R 
    The second PGI invented variant, the 6R focuses on a mixture of Snub-Nose PPC's and LB 5-X AC's. The PPC's take positions in the Arms and Torso locations while the Autocannons are located in the right and left torso respectively. Giving this variant a deadly combination of both energy and ballistic capability, and able to put out serious withering fire. The 6R carries two tons of LB-X reloads and single ton of missiles for the efficient Streak launcher.[13]
  • FNR-J(LGD) The Juggernaut 
    The Fafnir Legendary 'Mech is a dramatic inversion compared to other versions of the chassis, being built around a 400-rated standard engine, endo steel frame and near maximum Ferro-fibrous armor to mount eight heavy machine guns, two in each arm and side torso, fed from a combined six tons of ammunition.[1]
  • FNR-WR Wrath 
    The Fafnir Hero 'Mech is PGI's take on Archon Peter Steiner-Davion's custom variant listed above. With MWO lacking Compact Gyros and C3 systems, as well as PGI seeking to restrict its missile hardpoints, the Wrath carries a mere four Rocket Launcher 15s, one in each arm and two more in the left torso, replacing the Endo Steel frame for ferro-fibrous armor instead with an extra ton of Heavy Gauss ammo carried in the right arm. The remaining weaponry and equipment matches the 4A custom.[13]

Apocryphal Content Ends

Design Quirks[edit]

The Fafnir has the following Design Quirks:[14]

Notable Pilots[edit]

See: Category:Notable Fafnir Pilots



  1. 1.0 1.1 1.2 1.3 Technical Readout: Jihad, pp. 184–185: "FNR-5 Fafnir"
  2. MUL online date for the Fafnir
  3. Technical Readout: 3067, p. 101
  4. Record Sheets: 3067 Unabridged, p. 175
  5. Operation Excalibur Ch. 19
  6. Combat Operations, p. 131
  7. Record Sheets: 3067 Unabridged, p. 176
  8. Record Sheets: 3067 Unabridged, p. 177
  9. Technical Readout: 3085, p. 191
  10. Record Sheets: 3085 Unabridged — Old is the New New, p. 121
  11. Record Sheets: 3067 Unabridged, p. 178
  12. Jihad Turning Points: Tharkad, p. 2, 13. The record sheet includes a hand actuator where it should have the fourteenth endo-steel slot.
  13. 13.0 13.1 13.2 MechWarrior Online "Fafnir Sale Page"
  14. BattleMech Manual, p. 91 BattleMech Quirk Table -Fafnir Entry.