The UNSC Themistocles was an Orion-class assault carrier in service to the UNSC Navy with an operational history stretching as far back as the 2510s up until the Guardian Crisis. One of the first in a new line of vessels designed in response to the rising Insurrection, the Themistocles and its sister ships boasted their own production facilities which enabled them to support prolonged mass military operations on distant Outer Colonies, making them a key part of the UNSC's strategy to counter planet-wide rebellions. After 2525, these capabilities also made them critical to the Navy's efforts against Covenant, supporting entire battle groups as fleet carriers, though this role brought many into direct contact with superior Covenant forces and resulted in the destruction of most of the class. The Themistocles was one of the few to escape such a fate, and was refit in 2543 as a support vessel. After its brief trials, overseen by ONI as it was commandeered to gather the SPARTAN-III candidates of Gamma Company, the vessel participated in and survived the last battles of the Human-Covenant War. In its wake, the Themistocles was tasked with a voyage through the colonies that had been lost during the war to reestablish contact and begin efforts for the recolonization of human space, complete with a complement of its own Spartans, briefly carrying Fleet Admiral Lord Terrence Hood as part of this mission. The vessel finally met its end during the Guardian Crisis in the same way as so many other Orion-class vessels; while providing a sacrificial rear-guard action to provide cover for evacuation ships.
Match, the Themistocles’ artificial intelligence program.
"What do I look like, a computer? Oh, right."
Match was the ship's "dumb" artificial intelligence program from 2553-on. She was created in 2550 for the purpose, however, an unidentified flaw in her programming prevented her from being trusted to serve in such capacity. However, she was kept in reserve and during the Battle of Earth assisted Lieutenant Commander Kimura and Lieutenant Coney in coordinating part of the defense of Japan. Taking a liking to the construct's quirks, Kimura requested her assignment to his new command, rescuing her from the possibility of deletion by oversight panels. Aboard the Themistocles, she performed as a general-purpose assistant rather than a full-fledged ship AI, as her glitches hinted at deeper potential problems and therefore unreliable by regulation. Her flaws seemed to develop something of a personality of her own, including a fascination with Smart AIs, and problems in her speech and communication centers. For example, she might use synonyms in common idioms, often leading to confusion, but she was well-liked by the crew thanks in part to her quirks.