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The Sangheili/Human-Marionette War, better known as The Accidental War, was a both naval and planet based war between several inhabitants of the Milky Way Galaxy, primarily the UNSC-ISE Alliance, the Unggoy, and the Mgalekgolo, against The Vincicitum Invasionary Task Force of the Marionette Mind (Navy).

The Accidental War
Battle 2

2592CE / First Age of Realization


2603CE / First Age of Understanding


Former Covenant Empire / Orion Arm


Mutual Peace Agreements




Vincicitum Invasionary Task Force


Grand Mastermind Erunus Mio

  • Human
    • UNSC Navy
      • Delta Force Fleet
      • Beta Force Fleet
      • 8th Fleet
      • Gamma Force Fleet
      • 7th Fleet
      • 1st Fleet
      • Theta Force Fleet
    • UNSC Armed Forces
    • ODST Forces
    • Earth Defence Platform Grid
  • Sangheili
  • Unggoy
    • Balaho Defence Force
    • Fleet of the Great Maternal
  • Mgalekgolo
    • Fleet of Divinity
    • Fleet of Hope
    • Fleet of Exacting
  • Combined Fleets
    • Combined Fleet of Adamant Hope
    • Combined Fleet of Necessary Aggression
  • Marionette Invasionary Fleets
    • Fleet of Horrendous Knowledge
    • Fleet of Righteous Intent
    • Fleet of Vengeful Justice
    • Fleet of Particular Decision
    • Fleet of Thoughtful Security
    • Fleet of Truth and Judgment
  • Marionette Armies accompanying the Fleets
  • Humans:
    • Numerous Vessels/Soldiers
    • Beta Force Fleet
    • 3rd Fleet
    • 8th Fleet
    • 9th Fleet
    • Emergency Aggression Fleet
  • Sangheili:
    • Numerous Vessels/Soldiers
    • Near destruction of the Vanguard Fleet
    • Fleet of Honour and the Sword
    • Fleet of Profound Realization
    • Fleet of Arbiter’s Valour
  • Unggoy:
    • Untold numbers of soldiers
    • Balaho Defense Fleet
  • Mgalekgolo
    • Numerous Vessels/Soldiers
    • Fleet of Exacting
    • Fleet of Hope
  • Numerous Vessels/Soldiers
  • Fleet of Vengeful Justice
  • Fleet of Righteous Intent


The War began thirty six years after the end of the Human-Covenant-Flood War. In those years, the UNSC (United Nations Space Command) of the Earth and the ISE (Imperium of the Sangheili Empire) of Sanghelios had assisted each other greatly in restoring their mutual powers, as they were constantly under threat from Covenant Remnant forces that had spread out to unknown regions of former Covenant Space. During this time, known to the Sangheili as the First Age of Realization, mutual gains and appropriations between the Humans and Sangheili accorded them superior wealth and expansion not seen since the early days of the Human Empire, and the zenith of the Covenant.
Even though neither side was yet at the power they formerly had before the Human-Covenant War, shared technology and several Combined Fleets accorded the two factions a superior military advantage over their enemies, and would come to aid them in the upcoming war. The Human Fleets had become so advanced by now, that most ships larger than a Frigate had adapted Energy Projectors, and the Marathon-Class Cruiser had been upgraded to the MK-II, and given two Plasma Torpedo launchers.
In addition, technologically speaking, the humans had been able to work on plasma technology so much, that they have been able to adapt and magnify its powers beyond even that of the former Covenant, making both human and Sangheili plasma weaponry far superior to that of the Covenant Remnants.


The War began in 2592, three years after the famous first transmitted message from the Marionette Fleet of Horrendous Knowledge:

"The Great Speaker once asked us to join him in life. He offered us death and taboo, and so we come to seek our vengeance"
― The Famous transmission from the Fleet of Horrendous Knowledge to the UNSC S-MAC Station London

A number of other transmissions were also received by Human and Sangheili forces, though the most remarkable and ominous of them all was the first. At this time, the Marionette Fleet had been hovering stationary in the Sol System for three years since the message was received, staying close to the gas giant, Jupiter. It numbered just over 200 ships, all practically identical, though minor differences broke them into two types, though neither of them seemed to have any mounted or concealed weaponry on them. During the three years, humans and Sangheili had attempted to repeatedly contact the Marionettes, but every attempt to approach or contact them was thoroughly ignored by the Marionette ships.
It was then in 2592, that the Sangheili and the UNSC decided to attempt a more direct method of approach, which the Sangheili had been pushing for about two years. The Humans eventually agreed because of disturbing reports of at least two other Fleets of similar description to the stationary Fleet had been sighted near both Balaho, the homeworld of the Grunts, and Te, homeworld of the Mgalekgolo. This was the final straw, after three years of unidentified ships and probes being sent across the system, even to places on Earth by the unknown presence, the UNSC conceded to direct methods. In a terrific display of military might, that had quickly repaired itself after 36 years of peace, the humans and Sangheili formed the Combined Fleet of Adamant Hope, numbering approximately 340 human and Sangheili ships. Several days of stalemate ensued, during which time both humans and Sangheili continuously relayed transmissions to the Marionettes, who again seemed to ignore them after issuing a single statement

The Fleet of Horrendous Knowledge has a single purpose, if you or any other wish to stand between it and that purpose, do so at your folly

First Battle of Jupiter

Date: 2nd July, 2592CE

Area: Jupiter, Sol System


  • Combined Fleet of Adamant Hope:
    • Assorted Human and Sangheili ships. (These ships had been rapidly assembled, and no formal record of their amassing exists)
  • Marionette Fleet of Horrendous Knowledge
    • 100 Hollow-Class Carriers
    • 200 Enlightened-Class Destroyers


Sangheili: Supreme Commander Dtar 'Zealonf

Human: Admiral Lord George Hood

Marionette: Grand Mastermind Erunus Mio


Pyrrhic Human-Sangheili Victory, Marionette defeat

The Battle

It is not known who fired the first shot, but at 13:32 on the 2nd of July, 2592CE, the Allied and Marionette Fleets engaged each other in a very close and vicious naval battle that eventually ended in a Pyrrhic victory for the Human-Sangheili Fleet. The Combined Fleet had been caught off guard by the manner in which Marionette ships engaged enemies, and by how they were defended.
The Combined Fleet had gone about usual tactics employed by Humans and Sangheili, creating a formation from which they could concentrate fire on the more defencively aligned Marionette vessels. Human MAC rounds hit home, but to their surprise did near nothing to the hulls of the enemy ships. The Sangheili at the same time attempted to barrage the ships with Plasma Torpedoes, but much to the horror of the Combined Fleet, almost all of the Torpedoes stopped in mid-flight, and turned back on the allied ships. Several of the torpedoes had made it through however, and caused some amount of dispersion among the Marionette ranks.
The Combined Fleet tried everything they could; Archer missiles, Plasma Torpedoes, all forms of projectiles aside from the MAC Cannons near always were seemingly caught in mid-flight and sent back. Energy Projectors, Lasers and MAC Cannons made it through, but Plasma weaponry was the only thing that ensured a decent amount of damage, MAC rounds having to be fired several times to punch a firm hole. In the mean time, smaller human and Sangheili ships were reported to be spontaneously exploding or being incapacitated by an unknown phenomenon.

During the Battle, two transmissions were received, but were only translated along with a third message received after the battle, around 17:27. In chronological order they were:

Why do you fight us? Do you seek to aid in his taboo?
Cease your assault now, or our purpose here is all for naught!
He will come for you, if he hasn’t already, and your thoughts will dwell upon your failure to see what we offered to you; salvation from assimilation, and safety from his lies

The Battle ended 14:16, the 2nd of July 2592, when unexpectedly the Marionette Fleet of Horrendous Knowledge fled the system via Slipspace with 13 casualties, including 11 destroyed ships and 2 with significant damage.
The Combined Fleet suffered a total 67 casualties; 43 destroyed and 24 internally disabled.

The War

Communications practically ceased between the two sides after the First Battle of Jupiter, 2592CE, only several random transmissions were ever received from the Marionette Fleets again for the next 11 years. Near to no transmissions were sent from the Allied front to the Marionettes, as it seemed that the Marionettes never heeded them.
In just under a year, both the Unggoy and the Mgalekgolo joined the Sangheili and humans, fearing the Fleets that hovered around their systems that had allegedly done such tremendous damage to the Human-Sangheili Combined Fleet of Adamant Hope.
More Marionette Fleets were found over the galaxy, in and around the former Covenant Empire, but mostly around occupied planets of Humans and former Covenant Species. The most significant battles are noted below.

The Second Battle of Sanghelios

2592CE, 1st Age of Realization (Click title for Battle Specs)

The First Battle of the Tala System

2594CE 1st Age of Realization (Click title for Battle Specs)

The Third Battle of Earth

2595CE, 1st Age of Realization (Click title for Battle Specs)

The Third Battle of Sanghelios

2596CE, 1st Age of Realization (Click title for Battle Specs)

The First Battle of Te

2600CE, 1st Age of Realization (Click title for Battle Specs))

The Battle/Destruction of Installation 02

2603CE, end of the 1st Age of Realization, beginning of the 1st Age of Understanding (Click title for Battle Specs)

Aftermath of the “Accidental War”

UNSC Admiral

Admiral Lord George Hood attending negotiations between the United Nations Space Command, Vincicitum Invasionary Task Force, and the Imperium of the Sangheili Empire

The Negotiations began swiftly and promptly. Inviting the Grand Mastermind, Erunus Mio and his Commanders to Earth, the Sangheili Arbitrator, Imperial Admiral, several Fleet Masters and High Councilors, and the UNSC HIGHCOM began discussions of negotiating peace on the 3rd November 2603CE.

The Marionette Commanders first considered the opening statements of the UNSC and ISE. They seemed surprised that their three years, unannounced presence over several of their worlds had been the primary cause for their direct actions against them.
The Grand Mastermind then explained the Marionettes perspective. Several Millennia ago, an extra-galactic threat had forced them from the Milky Way Galaxy to defend their homeworld. Realizing the Forerunner were suffering from the same affliction, the Marionettes entered a seemingly endless war that finished in Marionette victory approximately 100,000 years ago. Unfortunately, approximately 55 years prior, the same enemy began to speak to them, taunting them to come and fight him, this being known by the Marionettes as “The Great Speaker”.
The Marionettes had however, remained at peace for many centuries, so had few Fleets that they could spare to a War. When enough ships were assembled and armed, the Marionettes drove into the Milky Way on a search and destroy mission to find and kill the Great Speaker, who had mysteriously remained quite.

Human and Sangheili interference with their designs had not been anticipated. The Marionettes followed the Great Speaker through mental patterns, however these seemed to be reverberating from all over the Orion arm of the Milky Way Galaxy. Splitting their Combined Fleet, they searched over the planets with the strongest reverberations.

(It was later found that they had been following mixed brain patterns from assimilated species by the Flood. As such, near ever planet or area they searched actually belonged to humans, Sangheili, Jiralhanae, and various other species that had come into contact with the Flood)

Because of increased interference by the UNSC and ISE, several of the Marionette Commanders had suggested that they remove them first before carrying out their grand design.

Zealot Shch Nodotee

Fleet Mistress Yamn ‘Zealonf after exiting a negotiation meeting

Negotiations continued for several months, ending for the most part quite well. Formal apologies were made on both sides, even though several bitter feelings remained.

Terms of the Peace Negotiations:

  1. All Vincicitum Fleets are to keep well within the laws and parameters of UNSC, ISE, and Allied space directions.
  1. The Vincicitum Invasionary Task Force is permitted to patrol within and outside of Allied Territory for traces of Flood infection for as long as they require so long as guidelines are adhered to.
  1. Allied Fleets are not permitted to interfere in Vincicitum affairs. All Vincicitum aberrations against or intended against Allied guidelines will be dealt with by the UNSC HIGHCOM, and the ISE High Council.
  1. Attempts at trade, negotiation, or transmission must be adhered to, and all Codes of War as dictated by the UNSC and ISE are in effect within the confines of the Milky Way Galaxy.
  1. Assistance to Vincicitum Fleets is prohibited except under direct order of HIGHCOM, or the ISE Government, as agreed to and adhered to by the Vincicitum Invasionary Task Force
  1. Any and all Prisoners of War, regardless of their state, shall henceforth be released from custody of their apprehenders and be returned to their respective territories. This is to be adhered to within one month of the agreement.
  1. Flood Forms found by the Vincicitum Invasionary Task Force shall be liable to the Vincicitum Command. All breakouts of Flood Infection must be appropriately dealt with in one of the following fashions:
    1. Plasma designated Energy Projector “Glassing” by ISE or UNSC Forces
    2. Orbital Plasma Cartridge MAC Bombardment by UNSC or ISE Forces
    3. Orbital Telekinetic Obliteration of the Area by the Vincicitum Invasionary Task Force.

A formal Alliance was proposed and made within 2 years of the wars ending. The Vincicitum Invasionary Task Force remained in the Milky Way Galaxy until the year 2634CE.
To the ISE, this new peace ushered in the 1st Age of Understanding.

The Accidental War

UNSC | ISE | Unggoy | Mgalekgolo | Marionettes | Covenant Remnant | Eayn Mercenary Guild

Major Confrontations

Second Battle of Sanghelios | First Battle of the Tala System | Third Battle of Earth | Third Battle of Sanghelios | First Battle of Te | The Battle/Destruction of Installation 02