Gotta flirt to save the world!!
High schooler Takuma Akutsu is terrified of human contact and just wants to live a quite life. Too bad he doesn't have a choice in the matter when nine Valkyrie sisters come barging into his home! They've tasked him with raising their level to fight off the monsters threatening humanity--and how will he do that, exactly...? By gettin' down & dirty to the max!!!
Note: The digital edition (1/30/2018) for this volume was released before the print edition.
— Description from Comic Vine community (comicvine.gamespot.com).
