Lotti Gellar serves as a Reasoner within Basion Academy's elite Space Squadron, where her leadership position earns her the moniker "Queen." She possesses brown hair and blue eyes, bursting with an energetic, loud, and temperamental personality. A fierce sense of justice drives her to champion marginalized individuals, especially common Gambee pilots facing bullying like Sara Cruz. Jessie Ignes remains her close friend, consistently supporting Lotti's initiatives.

Initially, Lotti commands her Space Squadron with a dictatorial hand, demanding absolute unity and describing the group as "as close as family, partners in life and death." Recognizing Sara Cruz's exceptional, Reasoner-like combat abilities despite her low status, Lotti persistently attempts to recruit her into this dynamic. Over time, Lotti matures, understanding the necessity of collaborative teamwork over sole authority.

A profound hatred for Ralph Werec, who murdered her older brother during his attack on Grabera Academy, fuels Lotti. She personally vows to kill him. This vendetta creates a complex link to Sara Cruz, whom Lotti later discovers is actually Sara Werec, Ralph's sister. Learning Sara's true identity provokes Lotti's violent fury. Yet this animosity shifts dramatically; by the series' end, Lotti transforms into one of Sara's staunchest allies, joining forces against Ralph.

Lotti remains unaware of Sara's true identity during their early encounters, though she suspects Sara conceals a hidden past. Her persistent, sometimes forceful overtures gradually build a connection with the initially resistant Sara. Their shared trauma from Ralph's betrayal—Sara's personal loss and disgrace intertwined with Lotti's grief for her brother—ultimately forges a powerful bond between them.