Reincarnated in Highschool dxd with a nen system

To assist God with saving the dxd world, a random man is selected from earth he is granted a system and nen to help him along the way.

The system will not have a lot of impact

This deviates from canon. There may or may not be a harem; that hasn't been decided for the most part. I will also be drawing inspiration from other anime and other fanfics.

Disclaimer: This is my first time writing, so constructive criticism is welcome. I own nothing other than the plot and my OCs.