In Harry Potter, the number one villain Voldemort has a group of fanatical followers, and these followers are called Death Eaters. This kind of mermaid is mixed with dragons, but they are all black wizards and good at black magic.
Voldemort’s childhood experience of his mother’s early death, his father’s abandonment of his wife and son, and his growing up alone in an orphanage led him to have a fanatical longing for noble blood. He advocated that the magic world should maintain pure blood and should not intermarry with Muggles. Therefore, the Lestrange family and the Malfoy family are Voldemort’s original supporters and the most loyal death eaters.