I can imagine City Hunter being a champion. He killed a shitload of armed to the teeth guys in close combat, eliminated Keys team with ease. He was also pretty smart, tracking Harrigan and the others in a big town, purposefully killing specific people to unsettle Harrigan even more and only ever got scratched by Harrigan himself.
Also, the others seemed sad and acting pretty respectful when he got killed.
There is never, ever an idication that he's a young Predator or anything, i go by what is actually shown in the movies, and this guy is an A-Class killing machine.