Eve Louise hails from Finland and celebrates his birthday on July 1st. Standing 183 cm tall with an image color of dual violet, he is a member of the band O★Z. Eve exhibits a kind, modest, and gentle personality, often appearing tranquil and reserved. He maintains a distance from worldly trends, sometimes seeming airheaded due to unfamiliarity with current events. He shares a living space with Guiltia Brion and holds a deep appreciation for the roasted coffee Guiltia prepares.

His background includes former service as a vampire hunter. This equips him with notable combat skills; he can simultaneously fight multiple adversaries without visible strain and effectively wield two swords against vampires. Despite his feminine appearance, characterized by lilac hair and blue eyes, he engages proficiently in combat. He serves as the host for the vampire princess Carmilla. She typically remains dormant within him, coexisting peacefully. However, consuming ketchup triggers her possession, causing significant disruption. During these episodes, her primary physical manifestation is the lengthening of his hair.

Eve's relationship with Guiltia Brion extends beyond cohabitation; he demonstrates a strong understanding of Guiltia’s emotional state and circumstances, positioning him as a supportive figure within their dynamic. His name, "Eve," carries feminine connotations, contrasting with his actual gender.

Throughout official media, including the anime series, Eve maintains a consistent presence characterized by his gentle nature and underlying combat readiness. His role as Carmilla’s host adds complexity to his character, though their relationship remains largely stable outside possession incidents.