Princess Arms is a female humanoid teenager with a slender body, cream-colored skin, an almost square-shaped head, long poofy blond hair, green eyes, a long pointy nose, buckteeth, and four arms. In both of her appearances, she wears a long, pale purplish-gray dress with lighter-shaded fringes and a dark-gray necktie, white gloves, black shoes, and a gold crown.
In her debut episode, Princess Arms' hair covers up her left eye, but both of her eyes are visible at all times in "Princess Turdina".
Princess Arms first appears in "St. Olga's Reform School for Wayward Princesses", in which she is one of several princesses enrolled at the school to be reformed. She, along with the other princesses, is inspired by the words of "Princess Marco Turdina" to revolt against the school's administration and overthrow the headmistress Miss Heinous.
In "Princess Turdina", Princess Arms has assumed somewhat of a leadership role over the other princesses after Miss Heinous' eviction. She organizes a ceremony in honor of Princess Turdina to thank her for inspiring princesses all across the multiverse to be true to themselves. Even after Marco is revealed to be a boy instead of a princess, Princess Arms still embraces everything that Princess Turdina stands for, saying "Turdina is a state of mind!" She and the other princesses stand up against Miss Heinous a second time when she returns to try and regain control of the school.
Click here to view the gallery.