Rod Reiss, often publicly referred to as Lord Reiss, was the true king of the Walls from 845 to 850. He sought to return the stolen Founding Titan to the Reiss family, by having his daughter Historia eat Eren Yeager.
Rod, like his daughter, was a rather short person. Though, unlike his daughter, he was a slightly overweight man with a round face, short black hair and a thin black mustache. He was typically seen wearing the clothes of a wealthy man, featuring a white button-front shirt with a black pullover vest, loose black pants and black dress shoes. However, when conducting the Titan rituals Rod wore a white shirt and pants with a long coat, as did the other Reiss males during family meetings.
Rod often appeared to have a calm, yet slightly worried demeanor. He spoke with great certainty and intelligence about the events of his daughter, Frieda Reiss, and his brother Uri Reiss, when they obtained and lost the Founding Titan. Rod maintained a level head throughout most of his time with Historia, Eren Yeager, and Kenny Ackerman. He even gathered his composure after Kenny grabbed him and began shoving a knife down his throat. However, when Historia crushed the serum, threw him, and bashed his claims of godhood, he became erratic and panicked. After the syringe was shattered on the ground, he began lightly crying and desperately licked it off the floor so that he could become a Titan himself.
Appearance: Rod, like his daughter, was a rather short person. Though, unlike his daughter, he was a slightly overweight man with a round face, short black hair and a thin black mustache.
Personality: Rod often appeared to have a calm, yet slightly worried demeanor. He spoke with great certainty and intelligence about the events of his daughter, Frieda Reiss, and his brother Uri Reiss, when they obtained and lost the Founding Titan.
History: Rod was the eldest son of his and Uri's father, the inheritor of the Founding Titan and the true king of humanity. Some time later, he was joined by a younger brother, Uri.
Rod Reiss in the story: On the day that Wall Maria falls to the Armored and Colossus Titan's attack, the entire Reiss family goes to a chapel to pray in a secret underground area. However, Grisha Yeager, a man from beyond the Walls, comes to talk to the family, asking Frieda to save the people inside the Walls from the Titans. Bound by the First King's will, Frieda refuses.
Source: Attack on Titan Wiki, available under CC BY-SA 3.0.