In the fires of the Horus Heresy, the Immaterium churns with the Warmaster’s betrayal. Even in the Segmentum Solar — where the Astronomican’s holy light still blazes from Terra — warp jumps are no longer safe. Geller fields flicker under daemonic pressure, traitor sorcerers stir hidden rifts, and every transit risks turning the ship’s cathedral bridge into a screaming battlefield of flesh and warp-stuff. The void between stars is now a place of paranoia, mutation, and sudden war.
Any time the ship activates its warp drive (short hop or long transit), the Chief Astropath, Navigator, or Void-Master rolls 1d100 openly. Apply these modifiers (Heresy-specific):
• +15 in core systems near Sol or Mars (Astronomican strongest).
• +5 near loyal forge-worlds or shrine planets.
• -10 near suspected traitor-held systems or Isstvan echoes.
• -20 if the Ruinstorm’s shadow reaches this far.
Roll once per jump. Outcomes affect ship stats (Hull/Shields), crew morale, and PCs. Results can trigger immediate 5e combat scenes aboard the ship while the void battle continues on the hex grid.
01–25: Smooth Transit
The Emperor’s light cuts through the Empyrean like a golden blade. Ship emerges on target with no loss of time. All Bridge Officers gain advantage on their next Ship Action. Crew morale rises; no damage.
26–50: Minor Disturbance (choose or roll 1d4)
Geller Flicker: Auspex screams with daemonic static. All psykers aboard take 3d6 psychic damage (DC 14 Con save for half). One random system loses 1d10 Shields for 1 round.
Temporal Echo: Time dilates. Lose or gain 1d6 hours/days (player choice). Crew feels uneasy; impose disadvantage on next Morale save.
Whispers of Betrayal: Faint vox-ghosts of the Warmaster’s voice haunt the bridge. Captain must succeed DC 15 Cha save or crew gains -2 to all actions for 1 hour (paranoia).
Solar Flare Interference: Mars-adjacent turbulence. Ship drifts 1 hex off-course. Void-Master can spend an action to correct with DC 13 Piloting check.
51–75: Major Peril (choose or roll 1d6)
Warp Storm Surge: Violent currents batter the hull. Ship loses 4d10 Hull and 2d10 Shields. All PCs make DC 16 Dex save or take 4d8 force damage from lurching decks.
Daemonic Incursion (Minor): Geller field tears for seconds. 1d4 lesser daemons (use Cultist or Daemonette stats reskinned) manifest in a random compartment. Immediate boarding-style 5e combat while ship continues moving.
Navigator’s Madness: The Navigator screams and claws at his third eye. Ship emerges 1d4 hexes off-course. Navigator incapacitated for 1d4 days unless healed (DC 18 Medicine).
Temporal Whirlpool: Time fractures. Roll 1d6: 1-2 = lose 1d4 weeks; 3-4 = gain 1d4 days; 5-6 = ship trapped in loop — repeat the last Ship Action at disadvantage until broken (DC 17 Arcana check by Astropath).
Traitor Sorcery Echo: Alpha Legion or Word Bearer ritual residue. One weapon battery goes offline for 1d3 rounds. Roll for hidden sabotage (DC 16 Investigation or risk critical failure later).
Soul Bleed: Warp predators graze the Geller field. Every PC loses 1 Hit Die worth of temporary HP. Crew morale drops; next Morale save at disadvantage.
76–95: Catastrophic Breach (choose or roll 1d6)
Geller Field Collapse: Full daemonic boarding! 2d6 greater daemons and swarms of lesser entities flood the ship (use Bloodletter / Plaguebearer stats). Cut to full-ship 5e combat map while the vessel drifts helpless in realspace. Roll ship critical hit automatically.
Ruinstorm Echo: The Calth-born storm reaches even Segmentum Solar. Ship is hurled 1d6 systems off-course. All systems lose half Shields permanently until dry-dock repair. PCs make DC 18 Wis save or gain a short-term madness effect (Heresy flavor: visions of the Warmaster’s triumph).
Possession Cascade: Key crew (or a PC) becomes vessel for a daemon. Immediate contested Cha save (DC 20). Failure = possessed NPC turns traitor mid-battle or sabotages a system.
Realspace Ejection: Violent translation tears the ship back into realspace. Take 6d10 Hull damage and emerge inside a planetary gravity well (emergency Piloting DC 20 or crash).
Astronomican Blackout: The Emperor’s light vanishes for 1d4 hours. Ship is blind in the Warp. Roll again on this table at +10 difficulty. Paranoia spreads — crew may mutiny if morale fails.
Warp Rift Birth: A tiny new rift opens aboard. 1 random Location (bridge, enginarium, etc.) becomes a permanent minor Warp rift until sealed by ritual or tech-priest (DC 22 Religion or Arcana). Daemons spawn every hour until closed.
96–00: Apocalyptic Cataclysm
The Immaterium claims its due. Ship suffers catastrophic Geller failure + Ruinstorm + daemonic incursion at once. Roll twice on Catastrophic table. 50% chance the vessel is lost forever unless PCs mount a heroic last-stand boarding defense. Survivors emerge scarred, possibly with mutations or Inquisition scrutiny upon return to Terra.
All hazards run on the same initiative track as void combat.
Boarding/incursion scenes become full 5e combat inside ship corridors (Astartes plate treats them as difficult terrain for mortals).
Successful hazard resolution can grant bonus Ship Actions or “Throne’s Blessing” rerolls.
Failed jumps can strand the party on a hostile world, forcing orbital support calls while the ship fights for survival above.
Heresy flavor always: choirs fall silent, black-and-gold livery drips warp-ice, vox-channels carry Horus’s distant laughter.