SO!
This is all basically Rose using his powers, and what he looks like up close

He's a swordsman, as you can see XDD, he uses, controls, and his body has completely become a shadow itself
No weapons can hurt him, his can melt his body into a shadow of a nearby object or person, so he can hide or attack someone, but he doesn't use his powers for a surprise attacks, XD he's more of an upfront kid when he's in battle
The only thing that can allow people to hurt him physically or of any other kind of attack, is if his body is exposed to a moonstone, not much is known about these stones, just that they're the most affective weapon for fighting Cursed Users

The scar on his left eye is from when he was attacked by a robber at his home, he didn't know of his powers at the time, and didn't know how to use them, so when the bandit swung his sword, it cut through his left eye. a magic healer, who's powers are not of Cursed Users, healed his eye but it left a huge scar, and caused his eye color in his eye to change to a silver color