The KotHaar are practical creatures, not known for flights of fancy nor leaps of imagination. So, it makes sense that they would create a weapon like this.
The TzHaar-Ket-Om is a large cylinder of obsidian, whose purpose is to be whacked against something with as much force as one can muster. The impact delivers enough kinetic energy to split rock, shatter bone and do tremendous damage to ones internal organs.
Elegant this weapon is not, but you cannot argue with its efficiency.