Caliban

Caliban was a forested death world and the Dark Angels' home until Lion El'Jonson returned from the Heresy and the planet tore itself apart. Knightly orders once hunted its Great Beasts; Luther's garrison later turned the world against the Lion. Only the asteroid-fortress of The Rock survived the bombardment and the Warp storm that followed. Luther’s civil war with the Lion shattered the Caliban System; Cypher and Azrael still carry that unfinished hunt from the Rock’s remnant across Camarth and Somnium theatres.