The curse originator could have been anyone...
Just a thought:
Hrek, a Hru of considerable age, was mated to Hrof and during a daytime sleep-cycle one day, a meteor hit and destroyed his mate and injured him as well. The last piece of Hrof that remained was thrown some hundred yards distant and landed in a river. Over the course of many years, the rough edges of Hrof were worn smooth, and yet retained a slight concave appearance.
Hrek, wise beyond even Hru standards, knew not what had taken his mate away but he knew something had to be done. He mourned the loss of Hrof, and over the waning years of his life, asked many times that she not be forgotten. His prayers, of a sort, were answered.
Some years later -
Perhaps a shift in a teutonic plate during an earthquake led to the uncovering of the piece originally, but Otar - a sculptor by trade - wasn't sure. All he knew was he had spied it while fishing at the local river, and in the years to follow it would serve his family well for generations as a center piece on their mantle.
Then, when a call was issued for the finest craftsman to help build a throne for the new King in Kaldor, Thira Orthon wanted something special to mark the occasion.
His grandfather, Otar, had acquired a fabulous piece of granite some years prior, and over time the stone came into Thira's hands through an inheritance. This rock had a natural smoothness to it, and easily formed the curled front and seat for the throne proper - with little work on Thira's part.
The curse comes from the deep connections of the earth to Hrof and her memory. Her remains were slowly worn away by the river water - and the sword, forged from a small piece of ore from that same meteor, then doused in water drawn from the same river - can reduce the effects of the "curse", given the natural harmony that both share when in close proximity.
I must admit to being extremely tired at this early hour, so hopefully this makes sense..lol