Highschool DXD X Nier X Drakengard Crossover Challenge

When Issei Hyoudou went to bed at night he was certain that his bedroom was a small room filled with his 'treasures' not the rotted out corpse of an old semi-buried building with a gaping hole in it. But before he can freak out, a robotic voice calls out to him for assistance. Upon locating the source, he is surprised to discover that the voice is a boxy looking object with two robotic arms. The object identifies itself as a Pod and discovers that Issei is a human. Soon he learns about the war, the machine and YORHA. To further add to his surprise, Issei discovers that a strange grimoire has attached itself to him. Alone in an unknown land with a small robot as a companion, Issei ventures onwards to find out how and why he was brought to this realm. Is he in the future or a parallel world?

NB:

Pairings are of your choice (Can be A2, 2B, Devola, Popola, Zero or anyone from DXD or the Intoners). Harem is optional.

Tactician/Less-Pervy Issei

This challenge is based off of TheOmega360's Overslept. I make no claim to his/her fanfic whatsoever.

To clarify: In the Nierverse, the grimoire is unsealed by machines and accidently activated. Discovering that all humans are extinct in this (time/world?), it decides to find a new contractor in an alternate (time/world?). Issei makes a contract with the grimoire in his dreams and it warps him to its location.

OPTIONAL: Issei can still have Boosted Gear and the grimoire can unseal it for him.

The grimoire will be sentient. It cannot speak out loud like grimoire Weiss, but it can communicate telepathically.

You can choose a name and design for the grimoire as well as what type of grimoire it is.

OPTIONAL: The grimoire can use magical attacks and feed Issei it's magic to use. It can also teach Issei spells.

Issei will be more physically fit than in canon.

I MAY MAKE CHANGES TO THIS CHALLENGE OVER TIME.