Drastic

Khan had achieved complete mastery over the Divine Reaper long ago but had never used it in a real battle. That last step consisted of the lingering sharp energy after his slashes, which kept cutting even when the attack's mana was depleted.

That ability had much in common with the nature of Khan's element. Actually, it was Khan's mana that had shaped the Divine Reaper's last step into that form. That was normal with martial arts, and those similarities pushed the Divine Reaper's mastery even further.

The evolution had brought Khan closer to his element. He had learned to feel its unreasonably destructive force and sense the entropy in his surroundings, eventually managing to channel it into attacks.

The world wanted to fall apart, and the Divine Reaper could fulfill that wish, too. Khan's new understanding had added fuel and power to the lingering sharp energy, allowing it to exploit the environment's entropy to cut deeper and more easily.