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Omega-Monthu is Baltar's basestar.

Aboard this ship, he pursues Galactica and her Fleet to Earth. Having not attacked the Fleet in numerous yahrens, Baltar is able to lull the Fleet into a false sense of security, allowing this eventuality to transpire.

From this basestar, he and his aide, Lucifer, launch an attack against the Thirteenth Colony and the remaining Fleet (Galactica 1980 #1#4). However, the tide turns on the Cylons, as Commander Troykus Adama integrates Earth's nuclear warhead technology into all the remaining Fleet ships—including the Vipers. Adama himself kamikazes his grandson's Viper into Omega-Monthu, destroying it and, it is assumed, killing Baltar and Lucifer in the process (Galactica 1980 #4).