The War Before and the Warrior After

Ever since they came to a truce four hundred years ago, humans and youkai have coexisted with each other more or less peacefully. But despite how much the governments liked to brag about how far society had come since then, it was painfully obvious just how much the humans still looked down upon and ostracized the youkai. And because of this, Tsunayoshi Sawada, who is already picked on for his low grades and scrawny build, works desperately to hide the fact that he is not human. However, in his second year of high school, it somehow gets out that he's a direct descendant of none other than Giotto Vongola, the one responsible for bringing about the truce between the humans and youkai, Tsunayoshi is forced to stop being a bystander and is thrown into the midst of a battle he'd been trying his hardest to avoid.