Battle of Installation 05
Delta Halo fractures the Covenant alliance and awakens a nightmare that threatens all sentient life.
The Battle of Installation 05, known as Delta Halo, ignites the final phase of the Human-Covenant war following the destruction of Installation 04. This conflict unfolds across the second ringworld discovered by both factions, where a desperate truce between UNSC forces and rogue Sangheili is forged to counter the resurgent Flood and the Prophet-led Jiralhanae. The engagement serves as the catalyst for the Great Schism, shattering the Covenant hierarchy and forcing former enemies into a fight for galactic survival.
- Primary Combatants
- UNSC Forces, Sangheili vs. Covenant Loyalists (Jiralhanae-led), Flood
- Key Location
- Installation 05 (Delta Halo)
- Central Figures
- Master Chief Petty Officer John-117, Arbiter Thel 'Vadam
- Outcome
- Covenant Civil War ignited; Installation 05 remains active but contested
Lore & Background
What began as a standard deployment dissolved into a three-way war for survival. The UNSC and Arbiter's Sangheili fleet, initially opposed, recognized the Flood and Loyalist Prophets as an existential threat to all species. This revelation exposed Halo rings as weapons of mass destruction rather than religious salvation, irrevocably shattering the Covenant's theological foundation.
In Their Own Story
The gravity lift hummed with a sickening violet glow, carrying the Arbiter upward toward the surface of Delta Halo. Below him, the lush greenery of the ringworld was choked by purple biomass and the screams of dying Grunts. He landed on a ridge overlooking a sprawling valley where the golden armor of Sangheili clashed with the red fur of Brutes. The air tasted of ozone and rotting flesh. As he raised his energy sword, the ground beneath him shuddered, not from an explosion, but from the awakening of something ancient and hungry that had been sleeping in the mud for millennia.
Reader's Guide
Loyalists established a forward operating base on Installation 05 to prepare for activation while the UNSC arrived to sabotage defenses. Simultaneously, the Arbiter deployed to investigate the Flood outbreak under orders from the Prophets, initially suspecting Sangheili heresy. The Great Schism erupted when Jiralhanae commanders betrayed and massacred high-ranking Sangheili leadership, turning the Arbiter against his masters. While Master Chief fought through surface defenses to prevent firing, the Arbiter led rogue Sangheili forces against both Loyalists and Flood infection forms. The battle concluded with a failsafe activation that destroyed the local Covenant fleet and destabilized the ring, forcing an uneasy truce between former enemies to escape before total destruction.
Did You Know?
- This event marks the first direct interaction between Master Chief and the Arbiter in the series.
- The Great Schism officially begins during this battle, splitting the Covenant into Loyalists and Separatists.
- Installation 05 is unique among known rings for having a massive, fully operational Forerunner city on its surface.
- The Jiralhanae's rise to power during this conflict was orchestrated by the Prophets specifically to replace the Sangheili.
More in Story & Timeline
Elsewhere in the Halo universe
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