Hanging upside down on the city gates, he waited for his target, making his move once the target presented his token and entered the gate. In the mere minutes when the guard checked the token to the target's entrance into the city, he leaped down and assassinated him, skinning him and nailing the body at the same time. He completed these actions in one fell swoop, making the act almost seem like a form of art.
The most wondrous part was nailing the body, completely making use of one's logical blind spot. Because there were no other possible places to hide a body, no one would expect to just look up and see a whole corpse nailed onto the city gates itself.
One could expect the shock when Xuanyuan discovered a body nailed onto the city gates the next day.
