Nack Tierce had dark brown hair, which was styled back in a somewhat spiky pattern. He had medium brown eyes and was somewhat tall when compared to the average of the other cadets from his squad. He wore the typical uniform of a member of the 104th Cadet Corps with a gray shirt underneath.
Nack appeared to be a warm-hearted person who cared a lot about his friends, which he did not seem to have much trouble making.
Nack takes part in a team navigation exercise in a group led by Thomas Wagner. Part way into the exercise, the group notices its ODM gear had been stolen. In response, they speed up their pace to warn the other group. They find the other group in the midst of a conflict with a gang of thieves and help disarm the thieves.
During the Struggle for Trost, Nack is assigned to the middle guard in Trost District. Shortly after the squad's deployment, the group is attacked by an abnormal Titan, which results in the death of Thomas Wagner. Eren Jaeger is injured trying to avenge him, and the squad tries to help Eren, but are all killed in short order, with Nack being swat out of the air by a Titan.
Armin would later report his demise to the remaining members of the 104th Cadet Corps, saying he died valiantly in the line of duty.