The Sea's Sacrifices

Every year, the merpeople sacrifice a beautiful virgin to a seemingly endless pit, in fear of the gods. They don't know that the pit is a rift in the seabed, leading to the underworld. So when it's Percy's time to be sacrificed, he wakes up chained to the throne of the demon prince of the underworld, Nico. demon!Nico/merman!Percy slash mpreg Nicercy