The third and arguably the best season of this series, the first focus is on Koneko's story as she and the rest of the Occult Research Club travel to the underworld for their summer training camp. The opening has Issei awaking in a very extra-large bed in a very extra-large bedroom with the naked Asia and Rias. The house was "remodeled" overnight into a 9-story palace of sorts where all members of the research club live,along with Issei's very understanding and unflappable parents.

The trip to the underworld starts right after class lets out and summer starts. While Issei's horn-doggery remains well above reasonably normal levels, he is starting to mature, both in his perceptions of life and his relationships with the girls; not so much that it would sour those of you that want to relive your lives through Issei's adventures,mind you, but he is discovering there is more to life and relationships that "just boobs." This is a very good series and, the icing on the cake is, it seems the story is far from over.