Isaac Komnenos Doukas
Isaac Komnenos Doukas (c. 1155–1203) was the eldest son of the sebastokrator John Doukas and Zoe Doukaina, and elder brother of the Epirote founders Michael I and Theodore Komnenos Doukas. In 1185 he joined his father at the Hagia Sophia in backing Isaac II Angelos' uprising against Andronikos I.
Around 1187 he married a daughter of Alexios Branas, shortly before Branas revolted against Isaac II. He was probably killed fighting the Fourth Crusade at Constantinople in 1203.