Cathal O'Toole was a Starfleet officer and flight controller aboard the USS Artemis. After returning from a conference with Daniel Radke to warn the Artemis crew of an alien conspiracy, he and 80% of his colleagues were killed when the Artemis was attacked by a then-unknown force in 2364. (Star Trek: The Prospect Chronicles: "False Security") The USS Prospect discovered, years later, O'Toole and the others were killed by a M'Tar attack. (Star Trek: The Prospect Chronicles: "Lady Lazarus")