Buzam A. Calessa, or simply "BC", is the sub-commander of the Nirvana. She is stern and all-business and looks after the general welfare of the crew. A skilled tactician, BC gives orders firmly and decisively. She seems like a workaholic, constantly staying near the bridge to access data and review the crew's performance.

During the initial episodes, she is seen secretly taking a small, data disc from the bridge's database, until Magno interrupts. However, her suspicious actions do not seem relevant until the Second Stage, where it is revealed that she is actually the Commander of the Taraak Intelligence, whose real name is Tenmei Uragasumi, a male spy for Taraak.

However, in the end, Magno Vivian forgives "her" and retains "her" position as sub-commander, on the provision that "she "stays as BC.