Imu's "contract" is a little hard to parse. So, by giving up some amount of your actual lifespan, you gain immortality. So, I guess the idea is if the spell breaks, you age faster. Kind of like the Energy Steroids from Fishman Island. Apparently, the "Coeurl" part is a reference to the story "The Black Destroyer"? That seems...weird and random. I guess I'm going to have to check that out, now. Apparently, it's about aliens, so...THAT's interesting.
https://en.wikipedia.org/wiki/Black_Destroyer
"Domi Reversi" mans "Returning Home" in Latin. Given my theories about dragons, I just have to wonder if they're actually basically being possessed by the spirits of those still locked away in the core of the planet? Those still trapped in the "Underworld" of the First World.
And Imu's power seems to be...Othello? Otherwise known as "Reversi". Okay, I didn't see that coming. Imu...LITERALLY has the power of a game. Okay, the Celestial Dragon's obsession with games makes a little more sense, now.
https://en.wikipedia.org/wiki/Reversi
I kind of wonder if Imu's going to have "Go" powers, too? It's a completely different game. But, it involves similar white and black pieces. Maybe even Chess or Tic Tac Toe? Is Imu's power JUST Othello, or does Imu have a entire Game Room as their power?!
So, wait, is Imu's giant gun actually a reference to Russian Roulette or something? I mean, it's not a revolver, but I wonder if that's the general idea? Is it supposed to be the Gun from Clue/Cluedo?! It actually looks a LOT like that classic board game piece. So, yeah, I think Imu's drawing powers from MULTIPLE classic board games! That's WILD!
https://cluepedia.fandom.com/wiki/Revolver
Even the pitchfork could be a reference to a game. There IS a board game called "Devil's Pitchfork", but I think that's a little too obscure for Oda to know about. But, since EVERYONE who gets "corrupted" by Imu also gets a pitchfork, I think it could be a reference to a different game. Onigokko, also known as Kagome Kagome. It's basically "tag", but those who get tagged also become "oni" and hunt down the others. I think this is the best fit for what Imu's doing. There's even a song. And it'd be interesting for Imu to have a song of their own to oppose Nika's Drums of Liberation.
https://bujinkansantamonica.blogspot.com/2012/10/onigokko-lets-pretend-we-are-demons.html
https://en.wikipedia.org/wiki/Kagome_Kagome