Seneschal Jorrude of the Tiste Liosan claimed the Tiste Andii were tragically imperfect in comparison to the Liosan as they had not received the benefit of Father Light's purifying blood. The Tiste Edur were tolerated because they carried something of Father Light within them. The Tiste Liosan were dedicated to Father Light's son, Osric.
Many millenia before the events of the Malazan Book of the Fallen, Vatha Urusander was the father of Osserc and the commander of Urusander's Legion. During the wars with the Forulkan and Jheleck, Urusander and his Legion were instrumental in saving Kurald Galain from destruction, but afterwards he accepted the Legion's return to a peacetime standing. Urusander retreated to his books and study. Thinking to keep his son out of a life of soldiery, he informed Osserc that he would not inherit command of Urusander's Legion. Osserc felt betrayed and abandoned his father.
Urusander's supporters and former soldiers, especially Hunn Raal, did not agree with his diminished standing and sought to force a political marriage between him and Mother Dark, while plotting to eliminate the ruling nobility through civil war. They began a campaign of violence and instability. Urusander was unaware of the actions Raal took in his name until it was too late and Kurald Galain teetered on the edge of civil war.