Mortrex

Mortrex is a world in the Ultima Segmentum that gave its name to the Parasite of Mortrex, a Tyranid bioform associated with Hive Fleet Kraken. The Parasite is characterised as an implant-based Tyranid organism, and the planet’s name serves as its title.

Hive Fleet Kraken used the planet’s crust as a nursery for the gestation of Ripper organisms. The Parasite of Mortrex is described as a winged synapse-beast, and later editions of the game depict it as a flying ovipositor. The Imperium’s census of the world was lost, and the world is not known to have produced any other distinct bioform.

Mortrex remains significant chiefly as the world that named the Parasite. Unofficial fan summaries place it in the Ultima Segmentum and do not classify it as a living tithe world. They also distinguish it from other planets affected by Hive Fleet Kraken, such as Devlan and Tyran.