Dirk Reiss (ディルク・レイス Diruku Reisu?) was the youngest son of Rod Reiss and his wife, the younger brother of Frieda and Ulklin Reiss, the older brother of Florian and Abel Reiss, and the half-brother of Historia Reiss.
Dirk was a 14-year-old boy with black hair and dark brown eyes. He was seen wearing a simple, light colored robe, a dress shirt, and a pair of black pants, as was common among the males during the Reiss family gatherings.
In the year 845, when Wall Maria fell, Grisha Jaeger invaded the Reiss home territory. He then transformed into a Titan and killed most of the Reiss family members including Dirk himself. According to Rod Reiss, he was crushed by Grisha's hand, along with his younger sister Abel.