He exists. I tried to pay my way thru finding him so I have others scouring the arena for his purple face. After more than 2 weeks a guildie found him but I was unable to join the arena for some reason. It always says Joined Failed.

After a few days I did my regular solo arena runs, was about to quit in the middle of a run cause I got bored and thought i'll do /partyi 0 and /partyleave instead. Then on the very last boss, stood the Challenger. I felt like the luckiest person in the world then hahaha.