A German university student, who is called the Prussian Devil. He is considered to be one of the most powerful Beatrice users in the world; despite his battle with Ayako resulting in a draw, Ayako was the one who ended up being gravely injured, while Johan barely had a scratch on him. Although, because Ayako was capable of fighting against him on equal footing, he aims to have Ayako as his bride, as he considers no one else worthy of her, especially Mamoru. Besides his outstanding Beatrice control, Johan is also very intelligent, and is on an expedition with Ayako's uncle researching the origins of Beatrice.