Aa Yuusha, Kimi no Kurushimu Kao ga Mitainda

Summary

I have only one goal: revenge towards the bully. "The ability to browse through all the world's books within my mind." The boy who was labelled as trash, Omiya Hoshikuzu deciphered the method to conquer the world from the world's books. He then headed towards the bully who came to be the hero. The boy who got transferred to another world along with his bully, will stop at nothing to fulfill his goal.