What is "andarzaghar"

Andarzaghar was a Sasanian commander that fought against the Muslims during the Islamic invasion of Persia. He was originally in charge of protecting the borders of Khorasan, but was ordered by the Sasanian king to protect the western frontiers from the Arabs who were plundering Persia. In 633, Andarzaghar, along with Bahman Jadhuyih, with an army composed of Iranians and Christian Arabs, made a counter-attack against the army of Khalid ibn al-Walid at the Walaja, but were defeated. Andarzaghar then fled, and died of thirst in the desert.