The story of the Eion class light carrier grows out of the Insurrectionist era and the Colonial Military Authority’s desperation for carriers to patrol the outer colonies. With the Navy’s aging carrier force stretched thin and showing flaws in their designs, it was clear a more modern light duty carrier was needed. Manufactured in the early to mid 2500s, the Eion class was a unique production run being built by both SinoViet and Reyes Mclees shipyards, a rarity for larger sized vessel which was usually produced by one firm or the other. Armed with a standard light MAC and a modest array of missiles and point defense systems, The Eion had the tonnage of the cruisers while retaining the versatility of a carrier in a compact hull that was often criticized as cramped by its flight crews. For the UNSC and CMA the light carriers provided crucial support with squadrons of Broadsword and Longswords in both defensive and offensive operations deep in insurrectionist territory. 

When the Human-Covenant war kicked off the Eion formed a critical part of UNSC battle groups, supplementing the heavy carriers or flagships with much needed support in the face of overwhelming waves of Covenant small craft. Sometimes they would be flagships for smaller fleets if an Orion class or Epoch was unavailable.  As the war dragged on, the light carriers proved valuable enough to preserve their numbers and were slowly pulled back to the inner world fleets where their numbers would be systematically decimated in various large scale actions. The only named ship of the class; UNSC Musashi, was destroyed in action over Reach in 2552.

The post-war years saw a fair number of the class remaining in inventory where they would return to their pre-war duties of rooting out insurrection on intact colonies paving the way for UEG recolonization efforts. While the type is slated to be replaced in service by more modern ships, the current state of the UNSC’s inventory means they will continue to patrol the galaxy for the foreseeable future.