Bäktär Borjigin dynasty

As a child, he was thrown out of the Borjigin tribe along with the rest of the family by the Taichud warlord Targhutai Hiriltug. Food was scarce and he, the eldest of all the sons of the late Yesugei, stole or kept food from his mother and siblings. Hasar and his brother Temüjin killed their half-brother Behter as he returned from a fresh hunt. After the defeat of Temüjin at Khalakhaljid Sands (1203), Hasar was lost and hid himself, along with his sons and followers, in the forest. Temüjin then gathered new adherents among the Mongols, tricked his rival Ong Khan with a fake message of surrender from his missing brother Hasar, and crushed the Keraites in late 1203.

Granted territories by the khan, Genghis Khan's full brothers Qasar, Khajiun, and Temuge formed the Left Wing of the Mongol Empire in the eastern edge of Inner Mongolia, while Genghis Khan's three sons, Jochi, Chaghatai, and Ögedei, made up the Right Wing in the western edge. The Right Wing saw a significant expansion to the west but the Left Wing did not have so much land to be conquered.