@imhikarucat
ah okay, then take it one step further then...
Dad is partially Cthulhu god and uses his only successful child with a human woman to fornicate with his full Cthulhu god in the outside realm to get Tooru which is full Cthulhu god in human realm.
So basically Dad is Tooru who is Cthulhu god.
Tooru thus slept with his mother to begat himself, then slept with his sister/daughter to begat himself.
Then I guess it makes sense why his Dad and his family doesn't think much of the sex cult. He was using them to get an infinite supply of women until he finally got a successful daughter.
Then after he remade himself in the human world, he was like, "I don't need these jerks anymore, time to rule the world."