Hmmm, interesting twist. I cannot wait to see how this story unfolds.

Not a bad chapter

I was not able to follow the fight at all. Ron is Fury? Or is it the red head? Who was happy the red head showed up? I thought Ron was winning the fight easily, but he was badly hurt? What is a rider? I can't even tell which side the red head was on. Who was armed with a whip? The fight seemed to be intended to introduce the protagonist and antagonist, but it only served to confuse me. I honestly think a re-write is needed.

I think you need to add more information in some way; I, for one, am not familiar with High School DxD other than from other cross-overs.

What is "Darksiders"?

Nice start ... lets see what happens from here :)