: Issei discovers he possesses the Boosted Gear , a powerful Sacred Gear containing the soul of the Welsh Dragon, Ddraig. This makes him a prime target and a pivotal player in global supernatural politics.

: Issei is thrust into an ancient, uneasy peace between three factions—Devils, Angels, and Fallen Angels—that nearly destroyed the world.

The series blends high-stakes supernatural battles with slice-of-life comedy and ecchi elements. Major story developments include: