Koike was a male admiral in Starfleet in the late 24th century. Commander DuVall reported to Admiral Koike in 2375, during the Dominion War. (SCE eBook: War Stories, Book 1; SCE eBook: The Future Begins)

In 2376, Koike permitted Commander Buonfiglio of the USS Hood to forgo its then-current assignment to sector 817, and join in the search for their missing captain, Robert DeSoto. (TNG - The Brave and the Bold, Book Two novella: The Final Artifact)