Can somebody please explain why nouns like "the Devil", "the Pope", "the Holy Spirit" need the word "the"?

Aren’t they all proper nouns and therefore supposed to not need the definite article?

The devil’s name isn’t “Devil.” it’s Satan or Lucifer or Beelzebub, etc. The Pope’s name isn’t “Pope.” It’s Leo XIV or Robert Francis Prevos.

I’m pretty sure they’re all distinct entities. There’s a whole Pantheon of demons, devils, and so forth. Lucifer took a third of the Angels with Her.

Hmm, her. What tradition are you coming from, exactly? I’ve heard the devil described as female before, but it’s usually “he” in my background.