Kolaghan

Kolaghan is one of the five elder dragons of Tarkir. She is titanic, covered in spines, features four feathered wings, and is able to breathe lightning. Feral and brutal, she enjoys the hunt and the kill more than the resulting meal. Unlike the other dragons, Kolaghan does not appear to speak draconic, only communicating in lightning flashes and violence.

Kolaghan's Brood
Kolaghan and her brood emerged from Ugin's dragon tempests armed with lightning breath and unmatched speed. They were drawn to Tarkir's arid hills and steppes.

Original timeline
Kolaghan and her brood were revered by the Mardu Horde for their speed. However, after Ugin's death, they lost the battle against the clans of Tarkir. No new brood was created and all died. Kolaghan never reached elder status and her skull was used as the throne of the Mardu khan.

Alternate timeline
After Ugin was saved by Sarkhan Vol, the brood thrived. The brood uniquely did not seek to tyrannically dominate their subjects, instead preferring simply to fly freely across the plains, striking down enemies and moving on. Even then, Kolaghan participated in the ban on the words "khan" and the names of the old clans.

Clan Kolaghan
The dragonlord became a fearsome leader, using violence, cruelty, and her trademark unpredictability to keep the clan in line. Under her reign, the Mardu name was forgotten, and the group became known as clan Kolaghan. Since the dragonlord rarely takes interest in the clan except to express her dominance, the Kolaghan follow other dragons from her brood that are born from the storms. The reckless Kolaghan take what they want when they want it, including power and dominance within the clan. The strongest dragons, the aggressive Warkites, are huge, strong, and battle-scarred. Non-dragon members of the clan are known to suffer from a powerful bloodlust called "the Crave". Cannibalism is not unusual, and the Blood-Chin orcs and humans seek out humanoid flesh. The Foul-Tongue Shamans of the Kolaghan use dark magic by perverting the Draconic language of Ugin into something sinister.

Unlike the Mardu, the Kolaghan follow no code of honor. Their ambitions are to raze the other Clans down and bring ruin wherever they go. The Kolaghan pine for freedom, from civilization, from limits, from any form of honor or law.