Tetsurri

Tetsurri was a malevolent ancient tyrant and former ruler of Zaterra though his name was only spoken of by Raiden as a forgotten legend in Mortal Kombat: Defenders of the Realm.

History
It seems that long ago, the ancient Realm of Zaterra was too also lorded over by a certain patriarch. A wicked warlord by the name Tetsurri who was born with a cruel nature as he made the entire Saurian kingdom into a desolate world under his rule before he died. After his death. his own beating heart filled ith such negative energy was then transformed into a crystalized version of it and also the very ruby-like demon stone, hence the name Gem of Tetsurri and he became a legend ever since.

Source

 * Defenders of the Realm - The Secret of Quan Chi