In 1999, the anime Ginga Eiyuu Densetsu Gaiden aired as the second installment of side stories from the Ginga Eiyuu Densetsu novel series. The anime follows the pre-Battle of Astarte accomplishments of Yang Wen-li of the Free Planets Alliance, as well as the continued tales of Reinhard von Müsel and Siegfried Kircheis of the Galactic Empire. The first story, Spiral Labyrinth, follows Yang as he gains recognition for his evacuation of civilians from El Facil. As a result, he receives a double promotion and becomes the subject of media attention. Yang investigates the Year 730 Mafia, a group of Alliance military officers led by Bruce Ashbey. Yang uncovers information that may have political consequences, discovering that Ashbey's wife claims he was murdered, rather than killed in battle. The Mutineer focuses on Reinhard and Kircheis, who are stationed on Hameln II at Iserlohn Fortress. When the captain is seriously injured, Reinhard assumes command of the ship. Reinhard's leadership is put to the test as he gains respect from the crew and makes difficult decisions. The Duelist has Reinhard learning about a mining rights feud between his sister's friend, Dorothea von Schaffhausen, and Count Herxheimer. When Count Herxheimer challenges Dorothea to a duel, Reinhard volunteers to be her champion. In The Retriever, Count Herxheimer steals a Seffle particle generator prototype and attempts to defect to the Free Planets Alliance. The Empire tasks Reinhard with retrieving both the prototype and the traitorous Count, but he is given only the cruiser Hässliche Entlein due to the mission's sensitivity. Finally, in The Third Battle of Tiamat, the Empire launches a large-scale military campaign against the Free Planets Alliance to commemorate Kaiser Friedrich IV's 30th year of reign. A significant battle ensues between the Imperial expeditionary force and three Alliance fleets, with Reinhard intervening to help shift the outcome of the war.