Nick

Nick's outburst during Eren's trial Nick could be characterized by the word extreme. Any attempt to interfere with his mission or the Walls was a sin and considered the worst possible offense in his mind. He never hesitated to make his opinion known and was extremely quick to condemn anyone who disagreed with him. This was displayed at the trial of Eren Yeager where he loudly called for his execution and publicly argued with a merchant who suggested sealing the Walls. Any viewpoint besides his own was considered sinful and horribly wrong. However, Nick's personality changed quite substantially when he witnessed the extent of the war. Since he lived within Wall Sheena, he never had to see the bloodshed, so the shock of seeing the destruction past the Wall mortified him. He never again condemned anyone or made public his opinions as he became very quiet. He converted into a bleak and depressing man; only willing to speak when it was absolutely necessary. He did still retain the secretive aspect of his personality, and refused to reveal any information about the Walls, even after seeing the horrors caused by the Titans. So great was his devotion, that even the threat of death could not sway him. Nick did show signs of changing his viewpoint before he was murdered. While he did not reveal any secrets about the Walls, he did give the name of someone who could. His allegiance may have been changing since, as Levi Ackerman theorized, he would not reveal any information about the Survey Corps to his torturer.

Nick was a very tall man and older looking with noticeable wrinkles on his forehead and around his eyes, which had dark circles over them. His hair was high up on his head and was parted to the left, with the sides and back being much shorter. He wore a black cassock with three bands near the top that had the symbols of the Walls.