Yes, please, no gameguard or related softwares. That won’t protect a thing about ToS.
The video shown isn’t a form of cheating but simply how bad the game deals with high ping. After casting the normal attack he walks and attacks again, since the attack appears delayed on your client due to slow connection he walks during a moment where he should’ve been still and this causes the desync/teleport.
On a side note, from addon coding point of view and as well player that’s been around for a while point of view: Most of cheats and things that happened are out of the scope of gameguards which protects the program at system-level and some game files against changes by using low level methods. In simple terms: They won’t do a thing, that’s not how ToS works.
All that adding a gameguard-like application would do for ToS is make it unavailable for Mac and Linux users. We already can’t run the KTos/KTest clients due to this reason (and even if we manage to, requires quite good effort and knowing what you’re doing).
So, again, please, don’t advocate the use of these without knowing if it would be effective for the game or not and how it would affect a part of the player base ><. We all know IMC doesn’t plan on making native versions for other platforms D: