Undiminished Entelechy

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Undiminished Entelechy
Production information


Assembly Forges[1]


Ket-pattern battlecruiser[2][Note 1]



1,782 meters (5,850 ft)[3][4][5][6]


862 meters (2,830 ft)[5][6][4]


90.7 million metric tons[3][7]


2 pinch fusion reactors[7]


2 Gablien-pattern repulsor engines[7]

Slipspace drive:

Ophon-pattern borer[7]


Nanolaminate hull plating


Corvex-pattern dispersal field generators[7]




Service information


September 22, 2552[2]

Participated battles:

Battle of Installation 04[2]


Fleet of Particular Justice[8]




Undiminished Entelechy was a Ket-pattern battlecruiser that served in Thel 'Vadamee's Fleet of Particular Justice during the Battle of Installation 04 in September 2552. A recreation of the ship's command center saw use as a training scenario for UNSC Infinity's Spartan complement in 2558.[9][8] Undiminished Entelechy was the sister-ship of Purity of Spirit.[2]


Naval service[edit]

Undiminished Entelechy was one of the first ships assigned to the Fleet of Particular Justice. During the Battle of Installation 04, Purity of Spirit and Undiminished Entelechy were secretly ordered to conduct a close-range survey of Installation 04 by the Minor Prophet of Stewardship after the arrival of Pillar of Autumn. During the ship's survey, she took aboard several Forerunner constructs and many records from the Halo's outlying installations, and several of its augur arrays attempted to learn the secrets of the installation from the control center. At some point in the battle, Undiminished Entelechy was boarded and infested by the Flood. Ultimately, the ship was destroyed by Supreme Commander Thel 'Vadamee to prevent the parasite from escaping the Soell system.[2]

The ship crash-landed on Installation 04, her crew already dead. The wreckage became covered by the installation's vegetation; the growth of the local flora was accelerated by the ring's damaged control system and environmental remediation protocols. All data and research contained aboard the ship were lost when Installation 04 was destroyed by John-117, along with the ship, on September 22, 2552.[2]


Through unknown means, the Office of Naval Intelligence gained details of the vessel for the Spartan-IVs' War Games training simulations.[2]

Production notes[edit]

  • Undiminished Entelechy is the setting of the Halo 5: Guardians multiplayer maps Truth, a remake of Halo 2's Midship, and Regret, its remix. The vessel, as with most of the fleet depicted outside the bounds of the map, is represented as a Sangheili Hekar Taa-pattern blockade runner rather than one of the contemporary hull types that were actually present during the battle. In-universe, this is an artistic conceit on behalf of UNSC Infinity's War Games simulator.[8] The real ship was one of several Ket-pattern battlecruisers within the fleet, as was her sister ship, Purity of Spirit.
  • Entelechy is the realization of a concept's potential. It can also be defined as self-determination or motivation.


List of appearances[edit]


  1. ^ As the 2009 and 2011 editions of the Halo Encyclopedia state that Purity of Spirit (the sister ship of Undiminished Entelechy) is a Ket/CCS-pattern battlecruiser, it is assumed that Undiminished Entelechy is as well.