I have this theory. There is a Lovecraft story called "The port of Innsmouth" where a private investigator is sent to a town to check out strange happenings and discovers that the locals have been breeding with these fish people in exchange for gold so they can create an army of half breed fish people. What if all those tentacle monsters are trying to do the same thing? They’re all trying to create half human squid girl-esque offspring in order to take over and destroy the land dwellers.
I'm watching a show where the main character is implied, through symbology, to represent Lucifer, the Morningstar