Barbarus System

The Barbarus System is the Death Guard's lost home star system in Segmentum Tempestus, a poison-fog gravity well of mountain Overlords and valley farms. Mortarion learned to hate on Barbarus, and the XIV Legion later recruited from the same toxic slopes that had raised him.

Humans could live only in the valleys; the high keeps belonged to xenos warlords until Mortarion and then the Emperor finished the climb. After the Heresy the loyalists did not leave a usable recruiting world behind them. Barbarus is a dead name on later maps, a feral-world system scoured rather than garrisoned.

The Barbarus System still belongs on a Heresy-era chart because the Death Guard's culture was baked here, not on some later plague planet. Unofficial summaries treat the pin as Mortarion's origin, not as a living 41st-millennium fortress.