- A Demon Sword of Thunder who can shape-shift to human form. In her human form, she is a quiet, sad girl. Elsa was born from the rage of the Old Knight when his daughter was slain. She has the same name as his daughter.
- After his defeat, she slays him with a misericorde, fulfilling the promise made by his real daughter and dying herself from the wounds she received fighting Cecily and Aria. She transforms into a sword by chanting "Shake off your slumber. The time is at hand. By the judgement of thunder, kill God" (眠りを解け。時は来たれり。雷の裁きを。-神を殺せ?).