The connection isn't just a direct continuation, it’s more like stepping into a room after a massive explosion and taking stock. The previous few volumes were all about that insane, world-shaking war against the Alliance of Hell, right? Volume 23, 'School Trip to the Underworld', feels like a deliberate, almost necessary, downshift. It's explicitly an aftermath story. The characters are physically and emotionally recovering from the climax in Volume 22, and the school trip framing is a brilliant way to explore the new political landscape they fought for.
We get to see the results of their victory firsthand in the Underworld. The peace they secured, the changes in the devil rating games, how the factions are realigning. It’s a volume of consequences and setup. Characters like Rias and Issei are dealing with the personal fallout of the war and their own power-ups, which is a quieter but vital thread. The pacing is slower, but it’s all connective tissue, re-establishing the 'normal' school life setting that got completely upended, before undoubtedly launching into the next big arc. For me, it works as a breather that deepens the world.