Amir Mahmud in his work Habib al-Siyar writes that after the battle of Merv, the body of Shaybani Khan was found under a pile of slain Uzbeks, having died of suffocation. The qizilbashs severed his head and then cannibalized him in an act of devotion towards Shah Isma’il. Shah Isma’il latter turned Shaybani Khan’s skull into a jewelled drinking goblet—an old tradition of the steppe nomads, from the times of Xiongnu—and gifted it to Babur while sending his other body parts all over the empire to be put on display.
The battle of Merv isn’t the only case of alleged cannibalism the Qizilbash in their religious zeal committed; for in the year 1504, an Aq Qoyunlu commander Murad Beg was “cooked on fire and devoured” on the command of Shah Isma’il.
Shah Abbas Safavid allegedly had a trained squad of cannibals in his court, who when commanded would eat alive the prisoners in his presence.