One is the oldest of the seven siblings, a fact she never lets her brother Four forget, teasing him about her seniority by a mere three seconds. One's appearance is that of a remarkable piasa-like monster with the ability to fly. She dons a pink hat adorned with the number 1, a playful nod to her birth order. Her light orange hair frames her face beneath the hat, and she sports a pink and white striped tank top paired with dark pink shorts. One's furry body is mostly covered in fur, except for her unique bird-like legs. With her wings and feathers, she can soar through the skies like a graceful bird. A fanart Seven Little Monsters cursor with One.