Pre-Heresy Setup (~000–004.M31)
• ~000.M31 – Triumph of Ullanor: Peak of the Great Crusade. Horus elevated to Warmaster; Emperor returns to Terra for the Webway Project.
• ~001.M31 – Council of Nikaea: Emperor bans Legion Librarius (psykers). Magnus defies it in secret.
• ~004.M31 – Davin & Horus’s Fall: Horus wounded by the Anathame on Davin’s moon. Healed in the Serpent Lodge via Chaos rituals (Erebus/Lorgar influence). Warmaster turns traitor, beginning his conspiracy.
Early Heresy – Open Betrayal (~004–006.M31)
• ~004.M31 – Burning of Prospero: Leman Russ (manipulated by Horus) sacks Prospero. Thousand Sons nearly destroyed; Magnus flees to the Warp and joins Horus. Webway breach worsens on Terra.
• ~005.M31 – Isstvan III Atrocity: Horus purges loyalist elements from Sons of Horus, Emperor’s Children, Death Guard, and World Eaters via virus bombing of the Choral City. Captain Garviel Loken and survivors fight on; Eisenstein escapes to warn Terra. Heresy officially begins.
• ~006.M31 – Isstvan V Dropsite Massacre: Loyalist relief force (Iron Hands, Raven Guard, Salamanders + delayed others) betrayed by second wave (Alpha Legion, Night Lords, Iron Warriors, Word Bearers). Ferrus Manus slain by Fulgrim. Three Legions shattered; survivors form the Shattered Legions.
Mid-Heresy – Galaxy in Flames (~006–010.M31)
• ~006–007.M31 – Shadow Crusade (Ultramar): Lorgar and Angron ravage Ultramar; Word Bearers and World Eaters vs. Ultramarines/Word Bearers split. Calth ambush (Know No Fear) cripples Ultramarines.
• ~006–009.M31 – Signus Prime Campaign: Blood Angels lured into daemonic trap by Horus; Sanguinius confronts Ka’bandha. Red Thirst/Black Rage worsens.
• ~007.M31 – Angel Exterminatus: Perturabo and Fulgrim quest into the Eye; Fulgrim ascends to Daemon Prince.
• Ongoing: Martian Civil War (Mechanicum schism); Thramas Crusade (Dark Angels vs. Night Lords); Tallarn (Iron Warriors tank war); Beta-Garmon (titan-heavy prelude to Terra); Shattered Legions guerrilla actions.
Late Heresy – Road to Terra (~010–014.M31)
• ~010–013.M31: Traitors consolidate; Solar War begins. Loyalists regroup (Guilliman builds Imperium Secundus briefly; Khan, Russ, Dorn defend). Massive attrition across segments.
• ~014.M31 – Siege of Terra:
• Solar War: Traitors breach the Solar System; void battles ravage Luna and outer planets.
• Bombardment & Ground War: Lion’s Gate falls; daemonic incursions; endless assaults on the Imperial Palace.
• Climax: Horus lowers shields on Vengeful Spirit to lure Emperor. Duel aboard the flagship—Horus slain (soul destroyed), Emperor mortally wounded and interred on the Golden Throne. Traitors routed.
Key Notes for Your Campaign:
• Total span: Roughly 9–10 years of open war after Isstvan III.
• Player Rule: Minor victories, personal heroism, or saved NPCs possible. Major outcomes fixed—Horus falls, Emperor enthroned, Imperium fractures into the grimdark 40k precursor.
• Tone shift: Early optimism (Crusade compliance) → creeping doubt → outright horror and pyrrhic stands.