Colossi

The Colossi were another race of ancients who, unlike their Elder counterparts, survived the End of the Elder Age, though few can now be found. Previously widespread, the remaining numbers tend to be scattered, with the greatest concentration of Colossi being found on the Forbidden Island, though a small number of them still wander the Icelands.

Background
True to their name, the Colossi were mighty beings, and were known for their tough skin which rendered them nigh invulnerable. Ordinarily peaceful creatures, the powerful Dark Meige Arlthrulaastan riled them in the First Great War and caused them to attack the Elders. However, in this process, Arlthrulaastan also revealed their weakness, for with her art Control, she pervaded their hearts, and with their hearts having been exposed, the Colossi became easy targets for the Elders. Even now, when one wishes to kill a Colossi, its heart must first be exposed before one can even try, for that is its only weakness.

Colossi Hearts
The reason Colossi hearts make them so vulnerable is because they are their only link to sentience. Without them the Colossi are like the giant source rocks they came from. However, with them, the Colossi are one of the most loving and devoted races existent. Much more faithful than humans, when partnered with a mate, Colossi remain with their mate forever, and when one dies, the other does too, for when they partner, their hearts are exposed to each other, and meld into one.

Many scientists and meiges have attempted to replicate this phenomenon, but without actual access to true Colossi hearts, the task proves itself nearly impossible. For when a Colossi dies, its heart turns into the same stone its being is made out of, and no art can resurrect it then.