Dark Wizards in Harry Potter followed many radical ideologies in order to cleanse the world of what they thought to be impure. These Dark Wizards could be found pretty much everywhere in the Wizarding World of Harry Potter and occasionally even came face to face with protagonists such as Harry Potter. J.K. Rowling displayed the struggle between evil versus good through many elements, one of them being the eternal discussion on the matter of Blood Traitors.
Source：https://www.cbr.com/harry-potter-blood-traitor-explained/
