I started researching the Gods in the keys and I found something about the nine circles of hell, where there is a place called Tartarus. Sound familiar? So now I am going to incorporate the nine circles of hell into it, but I am going to call it the nine gates of hell instead and instead of the bosses from Dante's Inferno, I am gonna use the Fairy Tail demons, though.
I feel like I am giving away more of the story than I should be, so Imma stop talking now.