Black Fire Burns the Sky: the Doctor of Chemistry's Road to Become a King During the Warring States Period

If you were reborn during the Warring States Period, in that era when all heroes came together and hundreds of schools of thought contended, what would you most want to do? As a doctor of chemistry, after experiencing all kinds of unspeakable pain, and returning to that war-torn but simple and warm era, "I" did live my best life...