High School DxD, Vol. 4 (light novel) Vampire of the Suspended Classroom

A SHUT-IN TIME STOPPER! ​After the recent trouble with fallen angels and Excaliburs, Rias is finally allowed to unseal her first Bishop—Gasper. Issei is thrilled to find that this new addition appears to be a cute blond girl...but his hopes are quickly dashed. Not only is Gasper a cross-dressing boy, he’s also a total recluse with the power to freeze time! As if getting a shut-in to come out of his shell wasn’t hassle enough for poor, perverted Issei, a peace conference among demons, angels, and fallen angels being held at his school is beset by terrorists! Could this mean the beginning of all-out war?