This is a named mob in the Plane of War. For an overview of all nameds in the Plane of War, their PHs, map points, and mapped locations, see this quest entry.
At 80%, it splits into 3 mobs called "a fragment of Narikor". Two of these mobs are Level 103 at 100% health while one of them is Level 108 at 80% health. DPS the yellow-/cons until they lock health (this first set of adds locks at 60%) and then DPS the red-/con. Once all three mobs are at 60%, the named appears again.
This process repeats itself when The Heart of Narikor reaches 40% and again when The Heart of Narikor reaches 20%.
Between the named and all adds, you're looking at about 80 million damage needed to beat it.