No FY is not an evil character .He doesn't kill people unnecessarily .He is only a goal focused MC who doesn't care about anything else.
He can became the most virtuous character ever if he can fulfill his goal by doing so. Similarly , he can become the most evil as well. That's what i like about him.
Gu world required him to become a evil person and that's why he did evil things .But as you know , he never displayed pleasure by killing people because he didn't care.
As Fang Yuan says "only eternal life is goal".
