Towa rules as queen of Raja, a small western nation. She inherits a magical tiara passed down her royal lineage. This tiara neutralizes deadly poison contaminating Raja's environment, primarily from depleted gold mines, but each use gradually wastes her body, causing severe weakness and threatening her life. Consistently prioritizing her people's safety over her own, Towa actively performs purification rituals even as her health fails. Her self-sacrifice extends to a group of fatally wounded ogres; recognizing their plight, she expends the last stored power of the tiara to "name" one, Hiiro, saving his life. This naming creates a profound bond, and Hiiro pledges unwavering loyalty, becoming her devoted protector. The tiara's extensive use, compounded by sabotage from her treacherous doctor, Chikuan, leaves Towa critically ill. Seeking aid for Raja's economic and environmental crises, Hiiro travels to the Jura Tempest Federation. This prompts its leader, Rimuru Tempest, to intervene. Rimuru provides Towa with potent medicinal honey that significantly improves her condition. Rimuru's team investigates the poisoned lake, uncovering an artificially maintained hidden magic circle causing the contamination, not a natural occurrence. They dismantle the circle, securing a temporary reprieve. However, agents of the powerful being Violet—who originally bestowed the tiara upon Towa's ancestor as part of a deal—intervene. Violet's subordinate, Lacua, reactivates the poison. Forced to use the tiara again, Towa's health plummets. Lacua then manipulates Hiiro, transforming him into a monstrous form. To save Hiiro from death after Lacua's attack, Towa unleashes the tiara's full power, sacrificing her own existence. She vanishes, seemingly lost. Violet acknowledges Lacua's actions violated the original contract and expresses appreciation for the generations of "entertainment" provided by Towa's lineage. Violet revives Towa as an apology and terminates the contract, freeing her from the tiara's curse. Following these events, Raja discovers a new iron mine. Rimuru facilitates a trade agreement between Tempest and Raja, transforming the iron ore into valuable magic ore and securing Raja's economic future. Liberated from the tiara's burden and with her nation stabilized, Towa governs without the constant threat to her life. She later attends events in Tempest, such as the martial arts tournament during the Nation Founding Festival, indicating her ongoing diplomatic relationship with Rimuru and his nation. Towa also appears as a playable character in the game "The Tale of the Demon King and Dragon Nation," where her abilities reflect the sacrificial nature of her former tiara power.