A long-time associate of An Lushan, Shi Siming joined the rebellion from the beginning and proved to be a highly capable military commander.
After An Lushan was murdered, Shi Siming eventually took control of the rebel state and declared himself emperor of Great Yan, temporarily reversing the rebellion's decline.
While a brilliant tactician, Shi Siming was infamous for his extreme cruelty and hair-trigger temper. He frequently executed his own generals for the slightest tactical retreat or failure, creating a culture of absolute terror within his ranks. As the war dragged on, his behavior became increasingly erratic and bloodthirsty, causing even his most loyal subordinates to fear for their lives.
In 761 AD, Shi Siming's paranoia turned toward his own family. He openly expressed his desire to kill his eldest son, Shi Chaoyi, in order to clear the way for his younger, more favored son, Shi Chaoqing. After a series of military setbacks, Shi Siming blamed Shi Chaoyi and ordered his execution. Pushed to the brink and supported by other generals who feared Siming's tyranny, Shi Chaoyi acted first. He led a group of conspirators to his father's camp and had him strangled. This second major patricide in the rebel leadership effectively broke the back of the rebellion, as it exposed the deep instability and lack of honor within the Yan state.