King, the Devil-Armored War God Has Arrived

There is a vast place called the Continent of Kings. There is a city called Haidu, where an ancient demonic family lives. They possess a kind of demonic energy that can make them very powerful. Among them, there is a pair of "brothers and sisters" who are the best at mastering this magical energy. The elder brother is named Kain and the younger sister is named Luna. A time traveler inexplicably traveled into the magic armor summoned by Kain, and took Kain's body and consciousness as his own. In the end, the time traveler discovered that the matter was not simple, but a conspiracy that had been planned for a long time...