The demon "Amon" conspires with "Astaroth" and pursues supremacy of "Dark Zone", and Hell's Nail is one of Amon's followers. In addition to depriving one's mana through dreams, she possesses the rare talent to "transplant" the deprived mana to another individual through surgeries. Stalking beneath the shadows of Dark Zone's interior conflicts, she switches between sides and transplants mana to both parties, for her own pleasure to enjoy the scenes of hopelessly stagnating battles and the self-destruction of those granted with mana that one couldn't bear. Upon hearing the conspiracy between Amon and Astaroth, she voluntarily named herself a follower of Amon. Overlooking the deceitful pact between Amon and Astaroth, this "Merchant of Death" performs surgeries for both demons. Their intertwining schemes shall weave the funniest show for the hedonistic succubus.
"If you desire ephemeral power, give me your dreams of future." She grants power, not "victory". For she will be, as always, the final winner.