The black substance that came from the sword covered half of Arthur's body before it stopped.
Before, Arthur could barely grab the sword with both hands, but now, he carried it only using his right arm.
One of his eyes turned black, and had a few dots inside, resembling a galaxy.
"What's happening to me?" Arthur thought.
The entirety of his right side was covered in that black substance, and even one of his fire wings turned black. It did not make sense.
Arthur thought that type of energy only belonged to these demons, but he had done nothing wrong, expect used the sword.
Perhaps the sword was a demonic treasure? Well, it would not make sense at all, as Arthur found it in a dragon-like temple, and there was a diary of a dragon right next to it.
It was all in vain, as Arthur lost his consciousness. Not that he was not awake, no, he was, but it wasn't him controlling the body.
The body moved for itself, and it was a good thing more people from the Doom Order showed up.