When the handmaiden Mannaflora was forced out of Heim castle and gave birth to the illegitamate child of the dynast king Dorgula Oberyth, a girl named Versalia Oberyth. Brantyn saw this as an opportunity to further his position in the order, and having told his brother to raise the child as his own, he later used knowledge of Versalia's existence to blackmail the queen and gain the position of Exarch.
He then used his new position to intervene in the political strife caused by the death of the king and his lack of a (known) successor to carry on his mantle of rule. After gaining the support of the wealthy and noble classes, he obtained the backing of the Holy Lodisian Empire to the north and founded the Bakram-Valerian kingdom, which was to be lead by the heir of the noble house Eltynaha due to their blood relationship with the late queen Vernotta. But as the heir was too young to officially claim leadership of the kingdom, Brantyn installed himself as the Regent, and then forged a treaty with the Holy Lodissian Empire resulting in the Dark Knights Losloirian to be sent to Valeria in order to help Brantyn expand his rule. In the game, Brantyn appears to be uninvolved in the conflict throughout Chapters One, Two, and partly in Chapter Three, before becoming the main antagonist as conflict rises between the resistance and the Bakram-Valerian kingdom in the beginning of Chapter Four.
Brantyn is fought and defeated near the end of Chapter 4 during the seige of Heim. He fights in the Unique Class of Dark Bishop.