Returned from Hell, Revenge Requires Me to Save the World

I woke up in front of the judgment seat of the Cerberus. Countless dead souls around me cried out that they were wronged, but how could those who went to 'hell' be innocent? I watched them being ruthlessly torn apart one by one. When it was my turn, I saw the majestic three-headed hell dog's eyes widening: "It's you! The master who saved hell from danger three hundred years ago, you have finally returned -"