It would be a death tournament in a separate pocket dimension that is the same size of our universe and both characters will fight to the death no holding back at all until one of the opponents is dead. The fight will be full detailed in multiple paragraphs. After the person who won the fight they would get sent back to their world.
プロンプト
Create a fight scene that will be in multiple paragraphs in full detailed and both fighters will keep fighing until one is dead.