Lord of the Secret Art! - Chapter 778: Lord of Space (End of book)

The strongest Hero in history, Nakamoto Keisuke.

He was summoned to another world in the spring at the age of fifteen years old, and when he successfully defeated The Demon King, he was already thirty-two years old. He had finished his role in another world and returned to Japan, but the reality that had been waiting for him was, “Middle school graduate with seventeen years of blank period” label. He couldn’t find a decent job and had no choice but to spend his days working part-time.

Before such a Nakamoto, a beautiful girl who self-proclaimed had come to return the favor, appeared. “I’m the reward for Hero who had defeated Demon King”, said Angelica, a girl who came from another world that persistently tempted Nakamoto to make her his wife. Together with a high school girl who looks like Elsa, his beloved girl that he lost in another world, Nakamoto with his cheats skills got caught in a harem life.

In a world where fate is dictated by prophecy, heroes are chosen by the gods, and Dark Lords are doomed to fall… Lucian Draeven refuses to play along.Once feared as the greatest Dark Lord in history, Lucian had the world under his iron rule—until the so-called Chosen Hero struck him down in a blinding flash of divine justice. The kingdoms cheered. The world rejoiced.Too bad Lucian isn’t actually dead.Having faked his demise and gone into hiding, Lucian watches from the shadows as a new Dark Lord rises, more reckless and incompetent than ever. Worse, the gods have selected another overly enthusiastic, sword-swinging Chosen Hero to bring “peace” once again.The problem? Neither of them have a clue how to actually rule the world.As kingdoms crumble, wars break out, and the balance of power teeters on the edge of collapse, Lucian comes to a horrifying realization:If the world is going to survive, then it’s up to him—the so-called villain—to secretly fix everything from the shadows.But there's just one little catch…Lucian’s legendary Dominions are still sealed, and the only way to regain his strength is by playing the role of a villain once more—spreading fear, manipulating his enemies, and pulling the strings behind the scenes.Now, as the oblivious Hero and foolish new Dark Lord battle it out, neither realizes that the true mastermind is watching their every move.Because if the world wants a villain…Then Lucian will be the greatest villain it has ever seen.

Our protagonist Caam is a man from Earth that was reincarnated into this world as a demon. In order to survive, he spared no effort in avoiding the sparks of battle and without noticing it, he became strong himself.