Demoknights are ♥♥♥♥♥♥♥ OP

well my friend decided to play as a demoknight after at sniper im killing him too much then he was in a server with ♥♥♥♥♥♥♥ 21 KILLS after months and months he goes to server to get around 64 kills and when we want to play 1V1 well its completely getting unfun and stupid since he's getting all the ♥♥♥♥♥♥♥ kills and hiding skills and ♥♥♥♥ but when i always find a way to get him he changes class and starts to kill me and then comes back as a demoknight and ♥♥♥♥....

valve why the ♥♥♥♥ did you put demoknights THIS OP and my friend says your playing like a baby well okay a few days as a demoknight BUT MAIN DEMOKNIGHT AND IF UNABLE TO KILL PASSES TO HEAVY? tell me if this is a fatal cowardly way to play a game or so bad in other classes that he's playing as a no skill needed OP demoknight. and also say if those demoknights should be highly nerfed or removed completely cuz this is getting awkward