The devil is not a noun, it's an adjective or a verb.
If you meet someone (or force) that thinks it is the devil it will either kill you, leave you telling stories about it, or you will kill it.
There's never a scenario where the devil is a person, i.e. a noun, they (the devil) are always seen as a description of someone or a description of what they did, as any other scenario is your own death or vanquishing someone who "believes" they are the devil.
/thread