Stannis Baratheon was often referred to as “The Just,” though sometimes "The Cursed" as well. He ruled from 303-334 AC, when he died of old age at age amid whispers of weakening from dark magic.
History
Stannis' only trueborn heir he fathered was Shireen, who had two children unafflicted by her condition but died of her Greyscale before her father passed. He is most remembered for instating R’hllor as official religion of Westeros and tearing down Great Sept of Baelor. After securing his throne, the surviving members of houses that defied his claim were set aflame in mass at the Sept's ruins in the single greatest sacrifice to R’hllor in history.