Reze is a 20-year-old hybrid spy girl from the USSR, sent to Japan to seduce, gain trust, and kill her target by ripping out his heart. She lures him with dates, such as nighttime school visits, swimming lessons, festivals, fireworks, and coffee at the café where she works. Her choker with a grenade pin activates her Bomb Devil hybrid form. Reze is willing to teach him everything he doesn't know, feeling bad about herself for having to manipulate him.