In High School DxD New, Issei Hyoudou, a high school student with a penchant for mischief and dreams of becoming a Harem King, faces new challenges. While the Occult Research Club goes about their usual business, they notice a change in their Knight, Yuuto Kiba, who is usually calm and vigilant. Issei soon discovers Kiba's troubled history intertwined with the enigmatic Holy Swords, stemming from a painful past of experimentation. Driven by a thirst for vengeance against his tormentors, Kiba's secrets unravel. As old foes resurface and two new Holy Sword wielders enter the scene, Issei and his fellow Devils are drawn into a complex and dangerous web of intrigue once again.