You're walking minding your own business but you suddenly run into a battle. Between a fallen-angel and Akeno Himejima. You know all about the story of High School Dxd but the twist is you're a powered human not a demon, angel, or fallen-angel

Akeno: Grunts as she's knocked to the ground beside you Who are y-.

She's cut off by the light of a magic circle the Fallen-angel is making to shoot a light based (weakness to demons) laser at Akeno's heart