The danger of this man definitely isn't below that of Yue Changkong. He is absolutely a character that would cause others to have a headache. No matter who was against that fellow, they had to be extremely wary about him. He uses poison and he is extremely sinister.
He chose to cultivate an evil art. He was lready an extremely dangerous character. Given his personality, it wasn't strange that he has cultivated an evil art. Because, his innate nature was already evil.