King Huai of Chu 楚懷王 (r. 209-205 BCE), personal name Mi Xiongxin 芈熊心, was a ruler enthroned at the end of the Qin period 秦 (221-206 BCE). He was a grandson of King Huai of Chu (personal name Mi Xionghuai 芈熊槐, r. 329-299), one of the last rulers of the state of Chu 楚 before Qin conquered this region.
During the reign of the Qin dynasty, Mi Xiongxin lived as a commoner. When the first rebellions against the Qin broke out in 209, general Xiang Liang 項梁 decided making Mi Xiongxin not only king of Chu, but giving him the leading position over all rebels that joined against the Qin.
Mi Xiongxin agreed and took first residence in Xuchi 盱眙 (modern Xuchi, Jiangsu), and after Xiang Liang's death, in Pengcheng 彭城 (modern Xuzhou 徐州, Jiangsu). He was wholly dominated by the warlord Xiang Yu 項羽 and was forced to accompany him during all his campaigns.
When Xiang Yu entered the capital of the Qin dynasty, Xianyang 咸陽 (modern Xianyang, Shaanxi), the warlord adopted the title of hegemonial king (bawang 霸王) and bestowed to the king of Chu the honorific title of Righteous Emperor (Yidi 義帝). Not soon thereafter, Xiang Yu had King Huai assassinated and made himself King of West Chu 西楚.