}}

==Background==

'''Tarsis Ultra''' was a Civilised World with some specifications typical to an [[Agri World]] and a long, harsh winter period during which it looked like a ice world. It was the turning point of the advance of [[Hive Fleet Leviathan]]. During the [[Great Crusade]], [[Roboute Guilliman]] led the assault on this world from which he was attacked by an unknown assailant but was saved by a native soldier. Guilliman then made a warriors bond with the trooper vowing to return should the world ever need his aid. A temple within the capital Erebus honours this along with the planets residents changing the name to include the [[Ultramarine]]'s name and the local [[Planetary Defence Force]] attempting to replicate the Ultramarine's [[Power armour]].

==The Demise==

However, despite the victory Tarsis Ultra would not be the same again. Despite their defeat, the Tyranids had left some form of vegetation behind that was consuming the ecosystem (albeit slowly), which forced the Imperials to send fire-teams to suppress it.²