Sen Katens, or just Sen, is a main character of Psychteria and one of the youths who winds up living with Cali Nightstone. Sen shares an antagonistic relationship with Cali and is both the least trusting and helpful to her.
Sen is depicted as a thin-fit Earthian. He has white hair styled to cover his right eye, and his dark grey eyes are somewhat slit like in nature. His usual expressions consist of disinterest or anger. Clothing wise he wears black boots, black pants, and a black sleeveless shirt. Additionally, he can usually be found wearing a white poncho over all that. He also wears a trademark, grey scarf that covers his neck.
Sen is the grumpiest of Cali's group. Though he is not mean-spirited, he is not shy about voicing his displeasure or standing up to a challenge, especially where Cali is concerned. Sen is also somewhat single-minded, as he focuses much of his attention to finding his sister's killer and avenging her death. Further, of Cali's group Sen is the most practical, being one of the few to choose eating Krubby's meals over starving.
When not grumpy, Sen tends to be conflicted and depressed, largely due to what amounts to survivor's guilt after the Great Cities Destruction.
Sen's primary weapon is Katars, which he is shown to have great skill with.
Throughout the comic, Sen is shown as a fighter. Though he uses his Katars often, he is shown to be good at many combat related matters such as hand-to-hand, dodging, speed, and the like.
Sen is the only (or one of the only) survivors of the Great Cities Destruction event. It is revealed in Volume 1, Filler Chapter 1 that Sen lived in one of the city orphanages with his sister Sylina. However, Sen left to seek out the Fenaur Warriors in order to learn more combat skills. By the time Sen returned, he happened upon his city destroyed and his sister slain. From that point onward, Sen traveled for a long time with one goal in mind: avenging Sylina. He met Cali while seeking out his target.