Starleen is an Alien with white skin. She has large mauve eyes with stars in her pupils as well as a cat-like mouth. Her floor-length white hair is incredibly fluffy, and is said to have the texture of "Cotton Candy", and it also has highlights of different colors at the ends of her twintails; pastel purple, pastel blue, pastel yellow, and pastel pink. She also has messy bangs covering her eyes. She sports a large black sweater with oversized sleeves, as well as black thigh high socks. She is also very tall, standing to be about 8 feet and 5 inches, and has an slightly chubby figure. She has a black string-like tail that has a blue crystal star at the end of it, the star resembling konpeitō. She also has a star on each side of her head, the same one that is seen on her tail. A soft blue-ish white celestial glow surrounds her.

Starleen is incredibly shy, introverted, timid, and soft-spoken. She is also very clumsy, and gets very flustered when shown affection. She loves eating sweets, and can eat a lot of food without gaining a single pound; chocolate, chocolate milk, cookies, and cake being her most favorites. Starleen shows affection towards those she trusts and/or is friends with. She is known to like cuddling and hugging people when she ever gets the chance, and also likes sleeping. Starleen also tends to get attracted by extremely cute and fluffy things, such as puppies or kittens. She can also be easily scared, for example she is not good with horror at all. Her reputation is higher than it's fair, as everyone around her seems to love her due to her cute appearance and cute personality, people often calling her "Cute", "Hot", "Squishy", "Adorable", or even "Fluffy".