The Tomain was a destroyer in service with the Free Worlds League Military during the First Succession War. In early 2787 the Tomain was deployed as part of a squadron led by a former Star League Defense Force Cameron-class battlecruiser that the Free Worlds League had purchased in 2782 and renamed the FWLS Rasalas. This squadron was tasked with destroying the Bolson Shipyards in the New Kyoto system, one of many such devastating raids against Lyran Commonwealth-based naval and aerospace manufacturing facilities conducted by the Free Worlds League as the Great Houses began the First Succession War.
The Bolson Shipyards consisted of five box-like construction bays in orbit around the large moon in the Kyoto system. In addition to being a major producer of both freighters and JumpShips, the Bolson Shipyards were also involved in producing WarShip support systems for various classes of WarShip as well as periodic refits. The Shipyards were a natural target for the League to strike at, and the defenses in the system had been increased to no less than five squadrons of corvettes and an AeroSpace Fighter formation, the Fifty-third Aerospace Interceptors, by the time the League task force arrived. The task force consisted of the Rasalas as lead vessel, along with two cruisers and three squadrons of destroyers supported by two reinforced wings of aerospace fighters. The Lyran Commonwealth Armed Forces had assigned command of the defenses to Hauptmann-Kommodore Ustus Tillbert, who had divided the naval and fighter forces into five seperate groups guarding five different approaches to the shipyards.
The task force arrived at the zenith jump point in the Kyoto system on the 14th of February and made a three-day high-speed approach from the jump point to attack the shipyards. The Lyran corvette screen attempted to intercept and block the League task force, with the Lyran Mako-class corvette LCS Augustus becoming the first casualty of the engagement after being mobbed my AeroSpace Fighters and then flanked by the Tomain and another League destroyer, the FWLS Ripper.
It took the FWLS Rasalas six minutes of battle to break through the corvette screen and begin bearing down on the Bolson Shipyards, but a suicide run by a Lyran Chippewa fighter into the belly of the Rasalas inflicted substantial damage, destroying the fuel store aboard the Rasalas that powered her drive and maneuvering engines. With no control over her trajectory, the crew of the Rasalas abandoned ship and the Rasalas rammed directly into the heart of the Shipyards, perishing along with the yards in a massive explosion.
The fifteen-minute engagement carried a heavy cost in addition to the loss of the shipyard; the defending Lyran forces lost almost a dozen WarShips and the bulk of the Fifty-third, whilst the League task force lost the Rasalas, seven destroyers and the majority of its aerospace fighters.
- House Steiner (The Lyran Commonwealth), p. 46, "The Bolson Shipyards"
- First Succession War, p. 66, "The Vacuum War"