When the gods try to kill all of humanity, a lone Valkyrie stands up to them to try and give them a chance. She instates a "Ragnarok", a 13v13 tournament. Fortunately, she not only has the added benefit of another god's assistance (that isn't the GOAT Buddha) but the people of earth have incredibly powerful abilities that would allow them to fight on an even playing field with the gods. TLDR; ROR with the human cast being MHA characters, also Izuku is a rizzlord