Extinct chapters
This page is dedicated in remembrance of all those Space Marine Chapters that are entirely and definitely very dead. This does not include chapters that fell to Chaos, so all those lost during the Abyssal Crusade aren't listed here.
Astral Knights
Sacrificed their chapter to destroy the Necrons' World Engine in 926.M41.
Crimson Castellans
This chapter was fighting against renegades from their own chapter when a Tyranid Hive Fleet came by and ate them both
Crimson Consuls
Seriously, don't put crimson in the chapter's title if you want it to live. Supposedly this chapter was taken out piece by piece by an alpha legionairre.
Emperor's Swords
Destroyed by the Alpha Legion who contaminated their recruiting pool and implanted subconscious triggers in their recruits.
Emperor's Swords again
Based on Bellicas, which turned out to be a tomb world. Begin face-palming.
Fire Hawks
Lost in the warp. Surviving members may or may not make up the Legion of the Damned
Knights of Blood
Sacrificed to a man in a desperate effort to protect Baal from the Tyranid and Khorne-Daemon smackdown. Due to their reputation as borderline-heretics, it wasn't rebuilt in the Ultima Founding.
Knights of Eternity
Another chapter presumed to have been eaten by the Kraken.
Obsidian Glaives
Chapter destroyed by the Red Waagh. Detailed in Sanctus Reach campaign.
Shadow Wolves
Fought along with the Black Templars defending their homeworld against a hive fleet. Notable for dying to a man with the last to fall being a battle brother keeping the chapter banner aloft; hardcore.
Tiger Claws
Lost in the warp, surviving members absorbed by their founders, the Astral Claws.
Wolf Brothers
Succumbed to the instabilities of their gene-seeds. Any survivors are now feral wulfen