Background
Asuma was born to Biwakoand Hiruzen Sarutobi the Third Hokage. During his Academy entrance ceremony, Asuma became friends with Kurenai Yūhi. In the anime, during the Chūnin Exams, Asuma was placed on a team with Kurenai and Raidō Namiashi. He later cheered on his classmates during the third round of the Chūnin Exams.
During the Nine-Tailed Demon Fox's Attack, Asuma along with the other young ninja were barred from participating in the defence of the village by Shinku Yūhi and the other senior shinobi. A few years after the event, Asuma would become an uncle to Konohamaru. He later became a chūnin, then a jōnin.
About seven years before the start of the series, he had a disagreement with his father and left Konoha to pursue his personal interests. During his absence, he became one of the Twelve Guardian Ninja, a group that protected the Land of Fire's daimyō, indicated by the sash on his waist. During this time he developed a strong friendship with the monk Chiriku, who would go on to become the head monk of the Fire Temple. Prior to returning to Konoha to resume active military duty, he accumulated a bounty of 35 million ryōon the black market, something he seemed to be particularly proud of since it was a testament of his skill, even bragging that his bounty was 5 million more than Chiriku. After returning to the village, Asuma resumed his jōnin duties and became a teacher of Inomatsu and presumably some more students. About twelve years after the Nine-Tailed Demon Fox's Attack, seeing his classmate fall into deeper self-pity from losing Obito Uchiha and Rin Nohara, Asuma, along with Might Guy and Kurenai decided to speak with the Third Hokage, voicing their disapproval of Kakashi being in Anbu with such bitterness and suggested instead that he be re-assigned as a jōnin sensei in the hopes of restoring Kakashi's kindness.