On the back of the Dumbledore card given by Chocolate Frog. He also appears in Harry Potter 1 Sorcerer's Stone, and on the back of the Dumbledore card presented by Chocolate Frog is Grindelwald, who is drunk on black magic and only with the strong, which is why Dumbledore can be close friends and even closer to Grindelwald, wanting to conquer the muggles and change the world.