Chronicles of Khaldun: Crux of Eternity
Iathacl the Storyteller
Lost Purple Man Tribesman
She of the Dying Light only made one brief reference to Iathacl, warning the Shields of the Sorrowfell and the Mourners of Saerun Road that he obtained a suit of powered armor and disappeared. Whether he died or went rogue is unknown.
Perhaps the truth will be revealed in his description in Old Country for No Men.