Spirits in Highschool DxD

Spirit realm. A mysterious place that no one can fathom.

Arriving in a completely unknown world, Shido found himself on a path that he must keep walking.

What would he find at the end? What will be his means? What be his goal?

Disclaimer: The origin of spirits is different from Date a Live. The plot might be completely messed up, but I don't care. All the anime used doesn't belong to me and belongs to their original creators.