Ryosuke Asakura: 6 books

Do perverted things to nurture my power! While Takuma has done a good job raising some of the Valkyries' levels, there are a few he still needs to give some tender loving care. Enter Misa, rowdy older-sister type, and Yakumo, frigid ice queen. Every experience point counts as they prepare for the war ahead...Can Takuma romance these hard-to-get maidens?

The valkyries, defenseless without lovers, come under attack by demons! Their only salvation lies in Takuma, Nanaki, and a level of perversion unlike anything the world has ever seen!

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...

Date or die!! Get naughty or humanity is done for! It's Mutsumi's turn to step into the spotlight! The soft-spoken Valkyrie finally gets to go on a date with Takuma, but idols are under a strict love ban-no dating allowed! That means they're gonna have to go incognito if they want to gain enough...

Do me the way you did my sisters. The Norn has landed in Midgard, and she's intent on destroying the valkyries! With Skuld's arrival marking the prelude to a larger battle between Odin's forces and the wicked gods, it's time for valkyrie elder sisters Ichika and Futaba to join the fight...and...

On the verge of being done in by the wicked gods' overwhelming power, the valkyries are in big trouble. However, just as hope seems lost, Takuma's sense of romance is finally stimulated-and it's about time! Parting with his past self, this new Takuma is ready to be a man and take the perversion to new heights!