Was it good violence or bad violence that caused the great flood?

a big part of all the violence was due to fallen angels having sex with women and creating were greek mythology came from. satan knew that from the seed of adam and eve would come the one who would crush satan. so satan tried to corrupt every blood line so the messiah would not come. I have seen you post so many times about God being the biggest mass murderer of all time. God was actually saving the human race.