Mary Saotome, a scholarship student at Hyakkaou Private Academy, rises through the ranks as a cunning gambler, leveraging strategic brilliance and an acute grasp of game mechanics to dominate her peers. Her humble origins fuel a relentless ambition to transcend financial constraints, manifesting in ruthless tactics such as manipulating classmate Ryota Suzui into housepet servitude after his debt accumulation. Her trajectory fractures upon confronting transfer student Yumeko Jabami in a rigged Vote Rock-Paper-Scissors match. Exposed for cheating, Mary suffers public humiliation and housepet demotion, spiraling into desperation and a mental collapse during a high-stakes gamble against Yuriko Nishinotouin that leaves her indebted and emotionally fractured. A subsequent debt settlement game partners her with Yumeko, their uneasy alliance restoring Mary’s status while tempering her arrogance. The prequel *Kakegurui Twin* unveils a younger Mary, prioritizing trust and camaraderie, notably through her bond with Tsuzura Hanatemari—a relationship whose dissolution hints at her later hardened persona. During this period, she strategically claims a gambling den from a student council member, cementing her reputation as a rising force. Post-redemption, Mary fiercely opposes the council’s oppression of housepets, rejecting membership and vowing systemic reform. Her rivalry with Yumeko evolves into grudging camaraderie, exemplified by collaborative victories like the Nym Type Zero game, where Mary’s analytical prowess proves pivotal. She navigates a tense alliance with Ririka Momobami, the council’s vice-president, challenging Ririka to break free from Kirari’s influence. Defined by resilience, Mary repeatedly rebounds through adaptability and tactical ingenuity, excelling at uncovering cheating methods, crafting countermeasures, and exploiting psychological vulnerabilities. Though growth softens her edges, she maintains a sharp competitive streak, often cloaking vulnerability with bravado—particularly around Ryota, whose loyalty she increasingly depends on. Pivotal moments include her whispered aspiration to claim the student council presidency, signaling ambitions to overhaul the academy’s power structure. Her journey mirrors themes of self-determination and resistance against systemic inequity, navigating a world where status dictates survival.