Hundred Planet Rebellion
The Hundred Planet Rebellion was a serious mass anti-Imperial rebellion taking place on worlds bordering the Veiled Region. While the Dark Angels were attempting to follow the path of the mysterious Cypher, they uncovered a mad priest named Alldric the Subverter. The heretic visionary would lead a swathe of planets in the region into open rebellion, resulting in the Dark Angels and several of their Successor Chapters suppressing the cultists and slaying their leader.
It has since been revealed that Cypher led the Dark Angels to the region deliberately in order to take revenge upon the Alpha Legion due to past false dealings with them.
- 1: Codex: Dark Angels (6th Edition), pgs. 36-38
- 2: Dataslate: Cypher - Lord of the Fallen - Everywhere and Nowhere