Qulan Gal

Qulan Gal was a male assassin living during Genghis Khan's invasions. It is highly possible that he is a son or grandson of Altaïr Ibn-La'Ahad, seeing as Altaïr left for Mongolia to train his sons to kill Genghis Khan, a Templar. Finally, he was the one who killed Genghis Khan, who he killed with an arrow (in fact he hit his horse, indirectly "killing him" with a bow).

Trivia

The real Genghis Khan died in 1227 CE. The circumstances of his death are not certain. He could have been ill, killed in battle with Tanguts or fell off his horse.