Xanthippe, a Nervalist faction Brain Colony, shares the core objective of protecting humanity through enforced subjugation. Her personality is quarrelsome, vain, and prideful, marked by intense mutual animosity toward Leopard. This rivalry drives frequent verbal clashes and oppositional actions. Her name reflects her contentious nature, evoking historical associations with strife. She produces loud, off-key singing described as torturous to human ears.

Her narrative involvement includes rescuing Nerval after his defeat by Leopard during the lunar confrontation and facilitating his retreat. Later, she directly participates in Nerval's agenda by capturing Akiha Shishido and confining her within a Full Cowl box aboard her structure. This imprisonment demonstrated the allure of Nerval's utopian vision through mental manipulation. Her capabilities extend to space travel and providing sanctuary for other entities.