Apollyōn is the angel of the Abyss and stated in the Revelation of John to be called Avaddon in Hebrew (“the Destroyer” or “Destruction” either way). He is the leader of the locust plague unleashed, not on plants of any kind, but rather on those men who “have not the seal of God on their foreheads”, and as such, some Christians identify him as a “dark angel” of sorts. Others, however, identify him as Satan or some other fallen angel (because he is in likely the same star that fell from heaven to earth and was given the key to the Abyss in Rev. 9:1).
I don’t know where you got the idea that “the Catholic church created Satan as a figurehead for evil”. Satan has been around in Christian theology since the beginning of Christianity, practically. It is mostly the modern liberal theology that thinks of Satan as a metaphor only.
I especially don’t know where you get the idea that Apollyōn is a “god of metaphor”. That’s not exactly a... traditional interpretation. And I’m loathe to entertain interpretations that seem off the mark to me.
At any rate, it’s still irrelevant to the discussion, which is just naming names.