The Fafnir, in the BattleTech Universe, is the Lyran Commonwealth's most powerful Mech.
The Fafnir weighs as much as an Atlas or Daishi, but it is relatively unique since it cannot wield missiles. It was created by Defiance Industries, who saw fit to create a successful Mech similar to their failed Defiance model. This was the result, and it was favored by the Lyrans during the FedComm Civil War.
The Fafnir is meant for a front line assault role, and with that in mind it is equipped with the largest weapon a Mech can carry: the ballistic Heavy Gauss Rifle. Most Mechs equipped with Gauss Rifles cannot equip other large weapons, but the Fafnir's chassis is meant to solve that problem, and it goes further; it can mount Twin Gauss Rifles, and ironically, that is its standard armament, along with Dual Inner Sphere Large Lasers and Dual Inner Sphere Medium Lasers. Though quite slow, it also has thick armor, and can carry a lot of alternatives to its standard armament, such as the favored Quad Light Gauss Rifles paired with Twin Clan or Inner Sphere PPCs, which is an edgy sniper mode, or other modifications that make the Fafnir fit in most assault roles. Its limiting factor is that it can only mount Ballistics or Lasers.
The Fafnir is well known for its large body, since it mounts Twin Gauss Rifles. The Mech is easily spotted and distinguishable, and can be brought down only with brute force on its legs. The problem is that once it gets within 600 meters of an enemy, its Twin Gauss Rifles can be deadly. A critical factor is it is not readily equipped with support devices, i.e. LAMS, making it significantly vulnerable to missiles and long-range Mechs, i.e. Longbow, Vulture, etc. Although it can carry multiple lasers along with its Heavy Gauss Rifles, that is an inadvisable move since it has little space for heat sinks, considering it has a large engine weight, high armor rating (making it heavier), Gauss Rifles, and a host of ammunition, giving it little space to carry extra heat sinks.
Archon Peter Steiner-Davion piloted this Battlemech in his bid to become Archon.