Introduction
Garsiwaz is the brother of King Afrasiyab of Turan, remembered in the Shahnameh chiefly for his central role in turning Afrasiyab against Siyavash, contributing directly to one of the epic's greatest tragedies.
Turning the king against Siyavash
Resentful or suspicious of Siyavash's growing popularity and influence at the Turanian court, Garsiwaz worked to poison Afrasiyab's trust in his son-in-law through manipulation and false reports, ultimately persuading the king to order Siyavash's execution despite the objections of the more loyal and clear-sighted vizier Piran Viseh.
Lasting consequences
Garsiwaz's scheming sets in motion the long chain of vengeance that dominates the rest of the Shahnameh's Turan storyline, as Siyavash's son Kay Khosrow eventually leads Iran in a sustained campaign against Turan to avenge his father's death.