Aqua originates as the Goddess of Water in the KonoSuba universe, guiding humans to the afterlife and worshipped by the Axis Order. Her appearance features blue hair partially tied with a water-molecule-shaped clip, typically wearing a vest, detached sleeves, thigh-high boots, and an extremely short miniskirt. She exhibits a childish personality with blunt emotional expression and a constant need for praise. Aqua wages relentless war against undead beings, particularly targeting the Overlord cast despite repeated failed purification attempts and punishments. Moments of kindness surface, like defending Albedo from ridicule. Her experience sending humans like Kazuma Sato to other worlds grants her deductive ability to recognize beings from Earth, such as Ainz, Tanya, and Subaru.

Her divine abilities include Turn Undead, a purification spell amplified by her goddess status to seriously harm powerful undead like Ainz Ooal Gown and knock Shalltear unconscious. She possesses a Divine Aura attracting undead, water manipulation capabilities demonstrated by controlling floodwaters, and magical resistance rendering her immune to time-stop and despair effects. Relationships involve constant antagonism with Kazuma Sato, who dismisses her goddess claims and calls her useless. She maintains friendships with Darkness and Megumin while teasing Chris about physical appearance. Persistent conflict exists with Ainz and his guardians due to her purification attempts, though tolerance gradually develops. She reacts fearfully toward Tanya after provoking rage by claiming divinity, requiring intervention from Subaru and Ainz.

In *Gekijо̄ban Isekai Quartet ~Another World~*, Aqua is among characters transported via wormhole to a desolate world dominated by rogue golems. Separated during an initial siege golem attack, she escapes with Mare, Rem, Ram, Wilibald Koenig, Rhiner Neumann, and Naofumi Iwatani. The group battles low-tier golems before reaching a village to encounter Alec and Pantagruel. Aqua participates in questioning Pantagruel about the world's mechanics and golem hostility. She later joins Subaru, Beatrice, Naofumi, and Pantagruel to locate Tanya's group. Her involvement extends to the final confrontation at the golem facility, aiming with the group to activate a dimensional portal. Established traits persist: she unsuccessfully distracts a rampaging siege golem during the initial chase and briefly clashes with Kazuma over his behavior toward Vera Mitrohina. The narrative confirms her continued inability to convince most characters of her divine status outside her original companions.