Obsidia System

The Obsidia System is the Ultima fortress well of the Astral Knights, the Chapter that spent itself stopping the Necron World Engine and left a keep the High Lords later gave to the Sable Swords. Obsidia is a Chapter fief, not a Black Templars homeworld.

After the Astral Knights died, Novamarines later pulled the planet out of a mutant war called the Twisted Convocation. The Sable Swords inherited walls already paid for in a Chapter's extinction. This overlay does not invent a Templar monastery here.

The Obsidia System still matters as a monument to a Chapter that bought the Imperium a World Engine's death. Unofficial notes keep the Ultima parent and refuse to file the pin under the Black Templars.