OP thor would rip him to shreds that makes him a Universe buster. those demigods u speak of are nothing to thor black holes, stars have not done anything to him he could sit in one all his life without trouble i mean this is what Thor fought against which is much greater than three "arcangels"
thor fought and killed this Universal monster which contained 10,000 gods in it
he fought this without OF and still killed it i dont have the full fight but this might help
and by the way when it says thor died it really means he lost his memory or somthing like that but this is what thor is capable of which is much greater than hao