Yggdrasil (Individual Mjolnir-class WarShip)
|Previous names||Winter Wolf|
FedCom Civil War
The first Mjolnir to be completed, the LAS Yggdrasil 's predelivery trials were expedited at Archon Katherine Steiner-Davion's request and the vessel was deemed fit for service in July 3062. The politically mandated haste in those trials led to doubts in the Alliance Navy about the Yggdrasil 's reliability, with minor problems with the sensor suite and jumpsail reefing assembly discovered. As of December 3062, the Yggdrasil 's current location was unknown even to Heimdall. 
The Robert Kelswa subsequently fought in the Battle of Tharkad on the 18th of August 3066; when a task force composed of the Kell Hounds, Clan Wolf-in-Exile, the Blue Star Irregulars and the Twentieth Arcturan Guards arrived in the system with a WarShip escort, the Yggdrasil was one of the Loyalist WarShips that moved to engage. Fighting in deep space alongside at least one other Loyalist ship, the Fox-class corvette LAS Robert Kelswa, the Yggdrasil engaged the task force's WarShip escort. The Allied WarShips, led by the McKenna-class battleship CWS Werewolf, defeated the Loyalist WarShips, but not before the Fredasa-class corvette Kerensky's Blues operated by the Blue Star Irregulars took heavy damage. The Yggdrasil was crippled in the battle, taken as isorla, refitted and renamed the CWS Winter Wolf; the Robert Kelswa was also damaged and taken as isorla, but both ships were subsequently returned to the Lyran Alliance under the Arc-Royal protocols. The damage taken during the Battle of Tharkad was extensive enough that the Robert Kelswa wasn't expected to be fit for service again until 3070.
The Yggdrasil jumped for Alarion, but the ship never arrived. It later took part in the liberation of Tharkad during the Jihad.  In 3074 a small task force consisting of elements from the Lyran Alliance Armed Forces, Clan Wolf-in-Exile, and several mercenary units hired by the Draconis Combine noble and businessman Chandrasekhar Kurita attacked the secret Word of Blake facility known as the Ruins of Gabriel, a former Star League Defense Force naval facility constructed in secret during the Star League Civil War and located inside an icy moon orbiting the fourth world of the Odessa system. The Light of Faith was one of the ships located at the Ruins of Gabriel at the time of the attack and formed a part of the Blakist defense of the facility; in the fighting between the two forces the Yggdrasil was damaged and the Baron-class destroyer WoBS Light of Faith was destroyed.
While the Blakists were able to beat the attack off, they poisoned the populated world of Odessa III. To deny information to their enemies, the Word of Blake stripped the base of all available information, destroyed the Naga-class Destroyer that was undergoing repairs within the facility, and programmed all their drone fighters to self-destruct.
The Dark Age
When Archon Adam Steiner called for the Archonettes to return their power to Tharkad after the Jihad the rulers of every Archonette dragged their feet, seeking to retain their independence and authority as long as possible, but only one - Duchess LaRue, ruler of the Inarcs Archonette - went so far as to openly defy the Archon. Duchess LaRue's public statements became increasingly insubordinate, but her bid for independence was cut short when the Yggdrasil appeared in the Inarcs system on the 23rd of June 3083. The Yggdrasil was escorting four Monolith-class JumpShips transporting the Second Bolan Guards LCT and the entire of the First Royal Guards RCT; the two formations arrested the recaltriant Duchess and secured Inarcs, with the Bolan Guards remaining on-world whilst the Royal Guards escorted the Duchess back to Tharkad for a very public trial for treason and subsequent execution.
The Yggdrasil was mothballed in orbit of Hesperus II during the Republic era but was reactivated and loaned to the Stormhammers splinter faction during the Falcon descent on Skye. The Yggdrasil dueled the Jade Falcon Nightlord-class Emerald Talon and barely survived during the Falcons' second and ultimately successful attempt to conquer Skye.
In 3145 the Yggdrasil was refurbished and returned to service, making it the only WarShip available to the LCAF. It was stationed at Hesperus II and supported by a flotilla of combat DropShips and aerospace fighters.
An Ask The Writers question regarding the disappearance of the Yggdrasil after the FedCom Civil War and her subsequent reappearance later in the Jihad received the following response:
Yggdrasil suffered a misjump on her return trip home, one that rendered her KF drive and transit engines inoperative. Using her projected course data and a lot of small, independent scouts to scour the systems in and along that route, the Lyrans managed to find the dead ship--with no small amount of sheer luck--several light-years off from one of her jump points (far enough that her distress signal was not received yet). The found a ship whose fuel supply and food stores had run out years before, starving off what remained of her stranded crew.
|— Herbert Beas, BattleTech Developer, 16 July 2014|
- Field Manual: Lyran Alliance, p. 25 "The Lyran Alliance Armed Forces - Aerospace and Naval Units - WarShips"
- Field Manual: Lyran Alliance, p. 153 "Rules - MechWarrior Rules - Mjolnir-Class Battlecruiser"
- FedCom Civil War, p. 175, "Tharkad"
- Field Manual: Updates, p. 165, "Ships of the Alliance"
- Field Manual: Updates, p. 69, "Admiralty (Star Wolves)"
- Jihad Hot Spots: 3076, p. 13
- Jihad Hot Spots: 3076, p. 38, "Timeline of the Jihad"
- Jihad: Final Reckoning, p. 52, "The Jihad In Review"
- Jihad: Final Reckoning, p. 128, "Word of Blake Naval Assets"
- Field Manual: 3085, p. 94-95, "Reclaiming Authority"
- Field Manual: 3145, p. 122