The book of Enoch guarantees they will burn. The fallen begged Enoch to speak to God to forgive them and to save their beloved children. God said it was not possible because they were a perversion of his creation. They are the nephilim blooded, the descendants of Cain. They are the Canaanites. Even a drop of their blood in your DNA is enough to condemn. They are not of God. There is no saving them.