Marie

A quasi-organic master control program for Mizuho's ship. Totally self-repairing and maintenance free. Hovers around in an innertube and on occasion plays a miniature guitar. Due to Kei fearfully striking 'him' during an initial escape attempt when Mizuho revealed her true identity, Marie's programming became scrambled, endangering both Kei and Mizuho. Communicating partly through indistinct sounds and through gestures, Marie is essentially a portable link to the ship's operating system. But 'he' is also capable of emotion, as witnessed by the romantic relationship formed between 'himself' and Miruru and his sorrow at their parting. Additionally, in the OVA they are implied to have sex, and both of them will become embaressed when they see others display affection. The implication provided in the series 'extras' is that Marie and Miruru are but extensions of the ships themselves, and thus are the ships.

(source: Wikipedia)