Elsa, a Demon Sword of Thunder, shifts into human form as a young girl with black hair and violet eyes. Her quiet, melancholic demeanor reflects deep sadness. Born from an Old Knight's rage and grief after his daughter Elsa died in the Valbanill War, she embodies his trauma. Viewing the knight as a father, she shows unwavering loyalty and affection despite his destructive path, yearning for greater paternal warmth. This unfulfilled need isolates her. Her elemental nature grants control over lightning and thunder. To transform into her weapon form, she chants: "Shake off your slumber. The time is at hand. By the judgement of thunder, kill God." Her story culminates when she fulfills the original Elsa's promise by executing the Old Knight with a misericorde after his defeat by Cecily Campbell and the demon sword Aria. Mortally wounded in that battle, she dies, completing her tragic arc of loyalty and sacrifice.