Tetra is a 16 year old girl with green eyes and brown hair that is bobbed, with the bangs clipped back with a blue barrette. Tetra is tall, but slightly shorter than classmate Viola Anton. She wears a blue hoodie that says "Gossamer Gryphons" on it, and has the school's mascot in the center. With that, she wears flared dark-wash jeans with light blue sneakers. She carries her things in her pockets, unlike the other girls, who all carry handbags or larger bookbags. Tetra is never without a necklace that was given to her by her godmother, that is in the shape of a sideways cross that holds both sides of the chain together.
Tetra is very much a down to earth person. She is known for staying positive in less-desirable situations, and she is also thoughtful and personable, and quick to respond to everything, especially when someone she cares about needs her. Tetra is very much involved in the lives of her friends, and is always seen with at least one of them. People describe Tetra as sweet and gentle, but if you ask certain groups of people, she is harsh, cruel and spiteful. She is condescending and typically counters the opinions of the people she dislikes, even when they are correct. She usually watches people from a distance before actually going up and speaking to them. Although she does not approach people and speak to them, she is very opinionated and is known by name for verbally calling out and slandering her enemies, barraging them with insults and sassy comebacks, usually rendering them either speechless or extremely embarrassed. She doesn't care about the feelings of others and doesn't mind trampling on others to get what she wants.
Brooklyn discovers her necklace after the spaces begin breaking down, but she also finds a prescription issued to Tetra for Haldol, an antipsychotic. That may reveal the cause of Tetra's extreme paranoia and unexplained, sudden need to converse with herself.
Tetra, like Aspen, shows a dislike and resentment for pet names and nicknames. However, she allows Callum to call her Four, like the Divergent books.