In 1370 Mu'izz al-Din Husain of the Kartids died, to be succeeded by his sons Ghiyas al-Din Pir 'Ali and Malik Muhammad. Pir 'Ali, a grandson of Togha Temur by his mother Sultan Khatun, considered the Sarbadars his enemy, and used the emigrant Sabzavaris in his realm to stir up discontent against Ali-yi Mu'ayyad. The latter responded by supporting Malik Muhammad, who ruled a small part of the Kartid lands from Sarakhs. Pir 'Ali then moved against his stepbrother, but Ali-yi Mu'ayyad stopped him by a flanking attack after overcoming one of Pir 'Ali's castles near the border, whose commanders were Sabzavaris. Pir 'Ali was forced to come to terms with his stepbrother. The fighting with the Sabadars, however, continued, and 'Ali was forced to throw his forces to defend Nishapur, leaving the western part of his lands exposed. At the same time, he made a hostile enemy out of Shah Shuja of the Muzaffarids. A revolt in 1373 in Kirman against Shah Shuja led by Pahlavan Asad received military support from 'Ali, but the rebellion was defeated in December 1374. The dervishes in Shiraz, meanwhile, found a leader in Rukn al-Din, a former member of Darvish 'Aziz's order. Shah Shuja gave them money and arms, and they conquered Sabzavar around 1376, forcing 'Ali to flee to Amir Vali. At about the same time, Nishapur was conquered by the Kartids of Pir 'Ali.