Psychopath

"Killing you will be an enjoyable experience." The Darkness Elementalist said icily while facing Klaus.

Of the group of four, Klaus was the one he hated the most because the first person to hurt him was Klaus, and he didn't hurt him alone, but he started to rub it in. And from his expression when saying it, it looks like he relishes the experience of hurting him.

"Hey, blockhead! Your opponent is me. We had an unfinished business, remember?" Grey called the Darkness Elementalist while changing positions with Klaus.

"I'll leave him to you, I don't want to defile my hands with his expired blood." Klaus turned to Grey fist-bumping him as he walked past him.

The Darkness Elementalist almost charged at Klaus when he heard this remark. This was the most annoying person he had ever come across in his life.