I would like to report this player as a hacker.
Guild: Dark Legends
I don't know how to put screenshots on here so there is all the information I can give.
If you do spend the time to actually search this player, notice his green orbs. They are all on the ceiling.
I attacked this player and I used a ghost potion. The ghost thief never moved at all, for at least the 2-3 minutes that I was watching.