Nothing. None of them exist. Their followers, though, have massacred, raped and laid waste to large chunks of humanity since way before the Dark Ages. Do you genuinely not know about the Crusades and the Inquisition. Or even the Vatican's tolerance for the likes of Hitler. Murderous rampages everywhere sky gods got dreamt up.
Sweet, loving Jesus, meanwhile, says I will burn in hell for all eternity if I don't believe in him. He can fuck off with that. Give me the good old Greek gods every day of the week.