There are lots of franchises that explore the concept of corruption. They use dark objects, serums, potions, and even more human elements like natural greed, lust, and hunger for power to explore the concept. As is often the case with these themes, it is difficult to tell if the dark object in question has turned someone evil, and corrupted them from their once pure potential towards a path of damnation — or if these objects are simply bringing out traits and qualities that are already prevalent within a character, but perhaps hidden just below the surface. The hubris of humanity means that these objects are often just encountering and drawing out qualities that the person already tends towards. This seems especially true for the rings of power in Tolkien’s world, which draw out the very worst of people, and drive them to do all sorts of terrible things.