Nathan is a physically fit man in his 30s with short brown hair and blue eyes. He wears a blue T-shirt with tan shorts and tennis shoes.
Nathan seems to be just an average guy, such as when he saw Travis injured on the pathway, he wanted to help him out like a good Samaritan only to find himself turned into a prisoner. As a prisoner, he becomes very paranoid and fearful for his life, begging to be let go and believes that if he constantly agrees to what Travis Marshall wants he'll be set free. He begs for forgiveness, even prays to God for it though whether or not this is sincere is up to question. He appears to be a relatively strong man as well. With enough patience and endurance he is able to break his chains from the floor. When he does get a chance to escape, he is quiet and careful about it...the only thing that gives away his position is the horse inside the church which both startles him and gets Travis's attention. Now, fearing for his life beyond any other measure, he begs for forgiveness with intensity, though it does not save him from being killed.
While Nathan is out jogging, he comes across a man in the road who is clutching his ankle. Nathan, wanting to see if he could help, rushes to him and the man named Travis Marshall tells him that his ankle must be sprain. As he tries to get a look at it, his head is met with a rock and he's knocked out, brought to a church to be a prisoner. The next day he wakes up chained to the floor by his hands, pulling at them with his strength. Travis walks in and tells him that in order to be saved, he must beg for forgiveness. Nathan begins to beg but he isn't believed at first, only upon the second visit does he get through to Travis. However, Gellar suggests that Nathan is just saying that to make Travis believe him and doesn't really mean it. Regardless, he claims he'll come around.
As time passes, he is finally able to weaken the shackles on the floor enough to pull himself free. He quickly checks the door, seeing as it would make too much noise to try and open it he instead walks through the main chapel and pushes aside a pew as he heads for the door. Unfortunately, a nearby horse rears up and startles him forcing Nathan to fall on the ground. Travis shows up and drags him back to the room, where Nathan crawls on the ground to beg for forgiveness. Travis looks on coldly as Gellar stands behind him, saying that he's finally ready.
The following day sees a very odd event, as four horses march through Miami with four riders. All four riders are mostly mannequin with human parts attached and when Dexter Morgan arrives on scene, he remarks how these are similar to the way his brother Brian Moser killed his victims. All the body parts are revealed to be from one man, who is later identified as Nathan Roberts. A piece of paper is also found in his left eye with the numbers 1242, which Dexter compares to the number of days between the victims deaths.