House Wyl of Wyl was one of Dorne's foremost great houses, with lands stretching along the Boneway on the border between Dorne and the Stormlands. Its rugged terrain was easy to defend and hard to attack, making it a vital defensive gateway to northern Dorne.
North of Wyl, the rushing Vale River formed a natural barrier that effectively held back invading armies from the Stormlands. To the east lay the reef-strewn Dornish Sea, where scarcely a day passed without fierce winds; to the west, dense forests in the Red Mountains surrounded it. The Boneway ran through the entirety of House Wyl's lands.
This exceptionally favorable geography gave House Wyl an enormous advantage in its battles against the lords of the Stormlands.
House Wyl was also notorious for cunning and cruelty. The Earl of Wyl during the First Dornish War, for instance, was known as the "Widow-lover." In year 12 of the conquest era, the tragedy at Oakhart Castle was carried out under the leadership of the Earl of Wyl of that time.
It was regarded as one of the most infamous events in the history of Westeros.
Their methods, however, were plain to see in their sigil: a black viper biting a heel against a yellow field representing the desert sands. Underhanded tactics such as poisoning and assassination thus seemed to be a source of pride for them rather than shame.
Beyond their skill at ambushes and assassinations, House Wyl had long fought the lords of the Dornish Marches to the north, giving them a thorough understanding of the strength and capabilities of the various houses.
To strengthen their defenses, House Wyl had dug numerous tunnels beneath their ancestral castle of Wyl, connecting it to natural caves in the Red Mountains.
During the Dorne War, Wyl's location made it an