Lovelock of Majestic War

A hero who manages world peace. There were twins who yearned for overwhelming power and vowed to become "heroes." However, a few years later, the younger brother, Yosai, loses his dream and becomes a cleaner who cleans the dirt from the heroes. Yosai is trapped in a position he was born with, looking bleakly at his older brother who became a hero. However, when Yosai sees the despair of his precious childhood friend Iruka, Yosai musters his resolve for the first and last time—all to defy fate. (Source: Kodansha, translated)