Rise of the Fallen Guardian Dragon

AU to my's Legend Resurgence. If you haven't read the Legend Resurgence, then I suggest you read that first before you read this one. Expect some lemons without warning! (Horrible at summary but I let you be the judge of that)(Harem otherwise it won't be DXD) (It is a mulitcrossover) Inspire by all DxD stories of Issei joined the fallen angels