Chagatai Khan

Chagatai Khan (c. 1186 – 11 December 1241) was the second son of Genghis Khan and the Khan of the Chagatai Khanate in Central Asia, after the death of his father. He was also the man charged to oversee the execution of the Yassa, the written code of law created by Genghis Khan. He was the uncle of the brothers Hülegü Khan and Kublai Khan.

Chagatai was killed by the Assassin Qulan Gal in 1241, while his brother the Great Khan Ögedei was simultaneously killed by Nergüi, in order to create a power vacuum and chaos in the Mongol Empire and stop the advance of Batu Khan on Europa.

Reference

 * Assassin's Creed: Memories