Stat Hax or Stat Bug

I got really curious these past few days as I was playing in siege then theirs this arcanist that has too high damage and at the same time too high hp, so after the siege almost all the players in siege said that he's hacking or bugging his stats, how did they do those? Can anyone tell me how did they do it?

Posted via Mobile Device.

There is no point in telling people the tricks since the method just gonna spread around the server and everyone will know it.

So people will probably not tell you the tricks.

ps, asking for a "Stat Hack/Stat Bug" on the official forum isn't the smartest thing to do.