The Bell of Lost Souls is a colossal iron bell that is as massive as a building and adorned with dark runes. It is located at the top of one of the many spires of the Imperial Palace on Terra. Thousands of minarets, towers, and spires rise from the Imperial Palace and breach Terra's ever-thinning cloud cover. One, and only one, of these towers stands out from its gold and marbled kindred as it is coloured jet black. It is called the Tower of Heroes. The summit of this looming structure is capped by a bell tower. The belfry itself is the size of a cathedral and houses a single bell forged of unassuming, commonplace metals, marked by the stains and patinas of time's eroding touch. This lone bell is the size of a Titan, and attended by hundreds of men, women and Servitors whose existence is entirely devoted to maintaining the sacred instrument's function.
The Bell of Lost Souls tolls only when the greatest of the Imperium of Man's heroes perish and can be heard by millions of people across the face of Terra. It rarely rings, but when it does, all resident Imperial Palace servants must be evacuated and sealed within reinforced shelters to prevent the annihilation of their eardrums and subsequent death through lung rupture and embolism. Among its many legends is the holiest of all; that when the bell rings, the Emperor of Mankind hears the sound even in His slumber upon the Golden Throne, and sheds a single tear.
The bell is inscribed across its entire surface with psychically-active hexagrammatic runes and its peal is said to sound like the scream of an anguished god, in this case the Emperor, mourning the lost lives of His children. Its wailing moan of grief lasts long and reaches the ears of millions, and its tones penetrate the unifying ether of humanity, turning the thoughts of countless billions towards the loss of Mankind as a whole. One of the most well-known, and recent ringings of the Bell of Lost Souls occurred when the Fire Hawks Chapter was declared "Lost to the Warp" in 963.M41 by the High Lords of Terra. That day, the bell tolled 1,000 times, once for each Astartes lost.
There is a special dispensation for the use of the bell concerning the Grey Knights Chapter. As the Emperor's only genetic inheritors amongst the Adeptus Astartes and Mankind's most valued and incorruptible protectors, the Bell of Lost Souls rings once each time a Grey Knight falls in battle. It is said that this is their reward in place of the recognition they will never receive from a galaxy that does not even know that they exist. A Grey Knight Battle-Brother will stand at the base of the tower in the sacrosant control chamber, surrounded by reverent serfs of the Palace and burning incense, and pull the levers that set the great, arcane mechanisms to work. Solar minutes later, the bell will toll a certain number of times -- once for every fallen brother. All of Terra will then know that the mighty have fallen, and that the Imperium is a darker place because of it.
When the order comes from the High Lords of Terra or the Emperor Himself, the attendant Palace serfs and Servitors will begin the laborious process of automated lockdown, broadcasting Vox-transmissions to send the belfry attendants into their bunkers. Another serf will start working the controls to awaken the continental communications relays. An overseer will then key in the one hundred and three ciphers required to unlock the safeguards that will allow his menials to access the deeper systems. The wondrous and terrible complexity of the Imperium's bureaucracy makes the entire process of ringing the bell take almost eight solar hours. When all is in readiness, a single servant will have one hand resting on the ornate control console and the other on the lever that will activate the myriad mechanics within the monument. When ordered to do so, the serf grips the lever, whispering a single name as he pulls it. The last lament for the fallen then rings out across Mankind's birth world, ignored by none and heard by all, as humanity's galactic empire mourns another of its fallen heroes.
Lost Chapters are those unfortunate Adeptus Astartes Chapters that have been destroyed or lost through some misfortune. Some were utterly annihilated in one swift and sudden strike, while others may have slowly diminished over a period of time through attrition or genetic instability of their gene-seed. Information in regards to such Chapters is sometimes lost or garbled during the long millennia and official sources are often all-too scarce. The following is a list of the known Lost Chapters:
|Astral Knights||Unknown||Unknown||Chapter was lost when it sacrificed itself against the Necron World Engine during the Battle of Safehold in 926.M41.|
|Black Consuls||Ultramarines||Second Founding||Recorded as annihilated during the Siege of Goddeth Hive by elements of the Word Bearers Traitor Legion in 455.M41.|
|Blades Eternal||Unknown||Unknown||Lost after entering the Eye of Terror in 321.M37 as part of the lamentable Imperial Abyssal Crusade.|
|Brazen Skulls||Unknown||Unknown||Wiped out as a Chapter by 773.M41. Circumstances unknown.|
|Brothers of the Red||Blood Angels||Unknown||Fatally undone by the genetic Flaw known as the Black Rage. Date unknown.|
|Chorus of Eltain||Unknown||Unknown||Lost after entering the Eye of Terror in 321.M37 as part of the lamentable Imperial Abyssal Crusade. It is unknown what they endured during their sojourn into the Eye, and they were declared Martyr Extremis by the Imperial Inquisition, considered to have been wiped out by the Forces of Chaos.|
|Crimson Axes||Imperial Fists||Unknown||Reported as lost as of 092.M39. Circumstances unknown.|
|Crimson Consuls||Ultramarines||Unknown||Destroyed through the foul machinations of the Alpha Legion Traitor Legion in order to secure their gene-seed stocks, which were delivered to Abaddon the Despoiler and the Black Legion to help replenish their ranks before the unleashing the 13th Black Crusade.|
|Crimson Legion||Blood Angels||Unknown||Chapter destroyed. Most likely undone by their genetic Flaw. Circumstances unknown.|
|Emperor's Swords||Unknown||Unknown||Decimated by the forces of the Alpha Legion after 300 standard years of infiltration and subversion. Another Chapter named the Emperor's Swords, which may or may not be the same group of Astartes, was wiped out in 970.M41 when a massive force of Necrons that had just awakened deep beneath their Chapter home world of Bellicas, assaulted their fortress-monastery.|
|Exsanguinators||Blood Angels||Unknown||Fatally undone by their genetic Flaw known as the Black Rage.|
|Fire Hawks||Ultramarines||21st Founding (Cursed Founding)||After being nearly driven to extinction during the Badab War, the Fire Hawks' mobile fortress-monastery, the ancient Void Fortress Raptorus Rex, was lost in the Warp in 963.M41.|
|Fists of Olchis||Unknown||Unknown||Lost after entering the Eye of Terror in 321.M37 as part of the lamentable Imperial Abyssal Crusade. It is unknown what they endured during their sojourn into the Eye, and they were declared Perditas by the Imperial Inquisition, who feared that if the Chapter still existed, it had been corrupted by Chaos.|
|Golden Sons||Blood Angels||Unknown||Chapter destroyed. Most likely undone by their genetic Flaw. Circumstances unknown.|
|Knights of Eternity||Unknown||Unknown||The Knights of Eternity were one of many Chapters who sold their lives dearly in the defence of the Imperium against the predations Hive Fleet Kraken in 990.M41.|
|Lions Sable||Dark Angels||Second Founding||During the unspoken period of history known as the Forgotten Wars (580.M31-632.M32), the ill-fated Lions Sable were completely annihilated during a disastrous campaign into the Eye of Terror whilst in pursuit of the notorious Fallen known as Cypher. Their subsequent fate and entire Chapter history was deliberately destroyed by the Dark Angels.|
|Marines Vigilant||Unknown||Unknown||Destroyed by the Crimson Fists Chapter on orders from the High Lords of Terra. The Marines Vigilant had come under the influence of a strange and rare Warp entity that had wiped away the Chapter's willingness to engage in combat. Tragically, the doomed Chapter put up no resistance at all as the Crimson Fists bombarded their verdant home world into a wasteland.|
|Obsidian Glaives||Ultramarines||Unknown||Annihilated when their Chapter Homeworld of Obstiria was invaded in 998.M41 by the vast Greenskin hordes of the infamous Ork Warlord Grukk Face-rippa and his Red WAAAGH!. Their current status is unknown.|
|Prophets of Mercury||Unknown||Unknown||Lost after entering the Eye of Terror in 321.M37 as part of the Imperial Abyssal Crusade. It is unknown what they endured during their sojourn into the Eye, though they were declared Martyr Extremis by the Imperial Inquisition, considered to have been wiped out by the Forces of Chaos.|
|Shadow Wolves||Imperial Fists||Unknown||Met their ultimate fate at the hands of a Tyranid splinter fleet in 987.M41 when their homeworld of Varadon was overrun by the xenos swarms.|
|Silver Stars||Unknown||Unknown||Unable to recover enough of the precious Progenoid Glands of their fallen Battle-Brothers, the Silver Stars could not cultivate further Astartes organ implants to create future generations of Space Marines for the Chapter. The Chapter quickly died off, unable to replace its losses.|
|Sons of Gideon||Unknown||Unknown||The Crimson Fists Chapter was called upon by the High Lords of Terra to exterminate the Sons of Gideon because they had been declared Excommunicate Traitoris after a routine examination of their gene-seed revealed that it had mutated to such an extent that the Space Marines of this Chapter had been driven insane by a chemical imbalance. The Crimson Fists mercilessly destroyed the Sons of Gideon's homeworld of Gideon IV and then hunted down the Sons of Gideon's 3rd Company which had escaped the initial assault. The surving Sons of Gideon had proceeded to butcher their way through the 4 billion citizens of the Colar System. Current status unknown.|
|Sons of Gorgax||Unknown||Unknown||Unable to recover enough of the precious Progenoid Glands of their fallen Battle-Brothers, the Sons of Gorgax could not cultivate further Astartes organ implants to create future generations of Space Marines for the Chapter. The Chapter quickly died off, unable to replace its losses.|
|Star Scorpions||Unknown||25th Founding||The Star Scorpions had the dual misfortune of producing highly mutated gene-seed and being utterly devastated by daemonic entities when the Chapter's fleet became trapped in the Warp. The High Lords of Terra decreed on the Emperor of Mankind's behalf that the Chapter should be considered irrevocably lost when the Adeptus Mechanicus proved incapable of using their corrupted gene-seed to reconstitute the Chapter.|
|Tiger Claws||Astral Claws||Unknown||Declared destroyed over fourteen centuries earlier and effectively a dead Chapter, a lone strike cruiser reappeared after having been trapped in the Warp and subjected to severe time distortion. The acting Chapter Master travelled to Holy Terra in an attempt to petition for the release of their Chapter's gene-seed in an effort to rebuild their lost Chapter. But subsequently the Tiger Claws envoy disappeared without trace while awaiting to petition their position and was summarily dismissed. Secretly joined the Astral Claws Chapter.|
|Venerators||Unknown Unknown||Unknown||During the 5th Black Crusade in 723.M36, Abaddon the Despoiler scoured the Elysia Sector, raiding hundreds of Imperial worlds and causing untold death and destruction. On Tarinth, the Despoiler lured the Venerators and the Warhawks Chapters into the ruins of Kasyr Lutein where he trapped them between the daemonic hordes of Khorne and the forces of the Black Legion. In a bitter last stand, both Loyalist Chapters were utterly destroyed.|
|Warhawks||Unknown||Unknown||Lured by Abaddon the Despoiler to the world of Tarinth during the 5th Black Crusade, both the Warhawks and Venerators Chapters fought to the last as they were utterly destroyed by both the Black Legion and the daemonic hordes of the Blood God.|
|Wolf Brothers||Space Wolves||Second Founding||Forcibly disbanded by the Inquisition and the Space Wolves as a result of the rampant genetic instability and resulting mutation that appeared in the Chapter's Battle-Brothers. Some of these renegades remain at large in the 41st Millennium, though the vast majority of the Chapter was liquidated millennia ago.|
- Codex Imperialis (1st Edition)
- Warhammer 40,000 Rulebook (6th Edition), pg. 163
- White Dwarf 99 (US), "Index Astartes, Legion of the Damned"
- The Emperor's Gift (Novel) by Aaron Dembski-Bowden