Ending the Tyranny of the Three-Headed Dragon by himself, thus saving the Underworld from total destruction, what happened to our Hero, Sakamaki Izayoi? Making a promise he once made to a family, will he keep it? A Gathering of Young Devils is approaching, what will unfold in the party? Will 'he' attend the Gathering? Marrying Rias, will he still be able protect her last?