Summary:

After the events of High School DxD, Issei Hyoudou finally achieves his dream of becoming the ultimate Harem King. However, a tragic—and ridiculously anticlimactic—death at the hands of a stray shoujo manga accident sends him into the afterlife... and straight into the reincarnation queue. Given his heroic deeds, the gods decide to give him another shot at life in a brand-new fantasy world.

Unfortunately for the locals, they underestimated just how OP Issei actually is—he's not just the Red Dragon Emperor, he's now every Dragon Emperor. With his boosted gear, an endless supply of power, and his perverted heart still intact, Issei begins a new journey where "overpowered" doesn't even begin to describe him.