I believe Zahard is too complex to be categorized as only evil or only good.
The way Ha Jinsung spoke about the goal of FUG was very clear to me, He left his family and everything behind just to pursue this goal.This can only mean one thing, Zahard did some bad things and it's normal, you can't just be the king of a Tower without making enemies along the way, especially when he's going to get blamed when any man of his empire happens to do something bad to someone else. Just look at people like Len/Ren, they're crazy as fuck but work under Zahard, who's going to get blamed if they do something that isn't liked or approved by many? Zahard of course.
I believe the royal enforcement divisions can also act without orders just like when Ren attacked Anak/Androssi because he felt they could be/become threats to Zahard.
However Zahard probably did some good things as well such as protecting everyone that belongs to his empire and probably many unknown stuffs.
I'm still wondering what's in the 135th floor and why Zahard is sleeping.
To summarize, A King is a King, he will always be hated by some and loved by some. And only him can know if deep down,he's evil or good.