Gath Rimmon

Gath Rimmon is a planet that once housed the ancient artifact the Ayex Commoragh, also known as the Heart of Agony. The planet suffers from acidic floods, which last for years. The only life on the planet are obsidian-skinned creatures that are hostile to any trespassers

History
The Ayex Commoragh was hidden on this world by Logis Alsmo Charis. An Eldar Warlock by the name of Valiel and a squad of Striking Scorpions hunnted Charis down to this world, but were destroyed by the Heart. In his last moments, Valiel left a psychic beacon on the roof of the cavern where the heart was locked away. Years later, a Space Wolf squad, led by Rune Priest Ravenblade, were drawn to this world. Ravenblade and Baldr Svelok, a Wolf Guard, managed to destroy the heart by flooding the chamber with acid at the end of one of the planet's cycles. Ravenblade died shortly after, because of his injuries, leaving the now one-armed Svelok the only survivor.