The Peace of the World A

After Qin unified the six states, Zhang Liang, a survivor of the Han state, harbored deep hatred for the fall of his homeland. He encountered an old man in yellow robes who taught him extraordinary arts. After mastering them, he lured Xiang Yu to seize one of the Nine Tripods, using its power to forge the might of ten thousand men. At the Battle of Julu, he swept through the Qin army and toppled the Qin dynasty. However, on the eve of peace, Zhang Liang secretly ordered soldiers to chant a sinister incantation at Gaixia, causing Xiang Yu's mind to be eroded by strange energy, turning him into a demon. Xiang Yu personally slaughtered Consort Yu, abandoned his army, and ultimately died alone at the Wu River. With one of the Nine Tripods destroyed, strange beasts roamed the land. Later, Liu Bang was besieged by demons at Baideng Mountain and nearly lost his life. Zhang Liang, witnessing the chaos and calamities he had caused, felt deep remorse and voluntarily resigned his title. Liu Bang, knowing his abilities, allowed him to establish a government office, naming it the Celestial Masters' Mansion, and ordered the Zhang lineage to eradicate strange beasts and bring peace to the people for generations. — Description from novelcodex.org