|In service until||March 2785|
When the Hegemony Armed Forces began to introduce the new Avatar-class heavy cruiser to service the decision was made to place the bulk of the older Aegis-class heavy cruisers in mothballs, orbiting the sun at a position somewhere between Terra and Mars, with a small number staying in active service as training vessels. The ship which would later be known as the Manaslu was one of the Aegis-class ships to have survived her service to the Terran Hegemony, and when First Lord Ian Cameron of the Star League chose to bring the Aegis fleet out of mothballs in 2582 two-thirds of the Aegis class went on to service in the newly-formed Star League Defense Force; the remaining third of the fleet - some 30 to 36 vessels in all - were sold to the various Star League member states. The Manaslu was either purchased by the Free Worlds League at this point, or obtained subsequently, and was still in service with the Free Worlds League navy in 2785.
In March 2785 the Manaslu was one of four Free Worlds League WarShips assigned to the defense of Bolan, serving alongside three League-class destroyers, the FWLS Talwar, FWLS Turk and FWLS Tyberium under the overall command of Colonel Salam Tutt of the Sixth Bolan Defenders. It was in early March that the Lyran Commonwealth launched an invasion of Bolan, deploying at least three regiments of BattleMechs escorted by eight Mako-class corvettes and four Commonwealth-class cruisers. The Lyrans split their forces, with one half arriving at the zenith jump point and the other half arriving three days out from Bolan via a LaGrange point.
The first WarShip engagement of the invasion came when the three Leagues engaged the first Lyran task group, damaging two Makos and forcing them to retreat, as well as nearly destroying a third Mako before the heavier Commonwealths were able to force the three destroyers to withdraw back to orbit. The first Lyran group managed to successfully land its ground forces and then engaged in a game of cat-and-mouse with the four Free worlds League WarShips until the second Lyran group arrived above Bolan, having burned into orbit from the zenith jump point. The Free Worlds League WarShips engaged the Lyran WarShips again, destroying two Makos and forcing a Commonwealth to retreat, but during the engagement both the Manaslu and the Tyberium were crippled.
The first WarShip engagement of the invasion came when the Talwar and her two sister ships engaged the first Lyran task group. Approaching along the solar plane, the first Lyran task group consisted primarily of the Caledonia and Donegal - both Commonwealths - and the Mako-class corvettes Aurelius, Nerva, Vespasian and Vitellius. In addition to the WarShips, the Lyran task force also included two squadrons of assault Dropships and aerospace fighters, and should have been enough to destroy all three League WarShips; however, the Lyrans were undone by the eagerness of the four Makos to engage the League WarShips. The four Makos ranged ahead of the heavier Commonwealths, accompanied by only light Dropship support, and as a result the Lyran task group was divided across too broad a front. The Talwar and her sister ships were able to use a combination of feints and sudden retreats to further disrupt the Lyran formation, damaging two Makos - the Nerva and the Vespasian and forcing them to retreat, as well as nearly destroying a third Mako before the heavier Commonwealths were able to force the three destroyers to withdraw back to orbit. The first Lyran group managed to successfully land its ground forces and then engaged in a game of cat-and-mouse with the four Free worlds League WarShips until the second Lyran group arrived above Bolan, having burned into orbit from the zenith jump point. All four Free Worlds League WarShips engaged the Lyran WarShips at this point with the Manaslu leading the charge, supported by a handful of assault DropShips and two squadrons of heavy aerospace fighters. The Tyberium had been heavily damaged by the Nerva and Vitellius during the initial engagement, but attempted to support the Manaslu as best she could; while the Manaslu inflicted heavy damage on the Caledonia, damaging the Lyran cruisers' port side fire control and her maneuvering drive, the Tyberium launched a suicidal attack on the Donegal. The Talwar and Turk were unable to assist either the Manaslu or the Tyberium, as they were locked in battle with the Aurelius and Vitellus; as the Talwar and Turk continued to battle the Makos, the Manaslu was savaged by return fire from the Caledonia, taking heavy damage to her prow, including strikes from at least two nuclear-tipped Barracuda missiles; the Caledonia was forced to retreat, but the Manaslu had lost her command centers, her sensor arrays and half her maneuvering thrusters, leaving her tumbling out of control. The crew of the Manaslu desperately launched escape pods even as the Donegal evaded the Tyberium's suicidal rush and crippled her engines. The crew of the Tyberium had no choice but to abandon ship, as she fell into Bolan's upper atmosphere and broke up, shedding escape pods right up until the last moment.
Although the Manaslu and Tyberium were lost, the Talwar and the Turk were able to destroy the Aurelius and Vitellius, and were ordered to retreat by Colonel Tutt when they detected the LCS Furillo, a third Commonwealth, burning towards the battle from the zenith jump point. After capturing the Bolan system the Lyran Commonwealth recovered the wreck of the Manaslu, but she was then scrapped after the Commonwealth declared her to be irreparable.
- Technical Readout: 2750, p. 132-133, "Aegis"
- Technical Readout: 3057, p. 144-145, "Aegis (Heavy Cruiser)"
- Technical Readout: 3057 Revised, p. 142-143, "Aegis (Heavy Cruiser"
- Interstellar Operations, p. 226-229, "Falling Into Fire"
- First Succession War, p. 19, "The Bolan Offensive"
- First Succession War, p. 21, "The Bolan Offensive"