Millie

Millie is the caretaker of all the pets of the main six, excluding Fluttershy. Millie is a full-grown unicorn pony with a white body, and a red mane and tail. She shares her design with Rainbowshine and Dizzy Twister. She has an assistant, Rocky, a little filly who is a Pegasus tomboy. Rocky's color is also white, and her mane and tail are blue. Her design is also the same as Millie.

Depiction in the series
Millie is a hardworking, kind animal caretaker who frequently appears in pet shops and pet supply shops, possibly to get equipment and companions for the pets she takes care of. She routinely disappears every day, making every pony in town puzzled. When the main six discover what she really is doing, she is just visiting her cousin, taking the pets along with her, as she cannot leave them alone in the house, at the request of the owners. Millie has a cutie mark of a circle of red hearts around a puppy much like Winona, but smaller. Millie was the very first one in her class to get a cutie mark, but however, she did not unleash her true talent until the main six ponies became friends. She then was a very good caretaker for the animals, excluding Tank. She later included Tank in the animals she took care of, after Rainbow Dash acquired her pet tortoise. She also did the same with Owlowliscious. Millie has a daily pet care routine. It seems that she takes care of many other pets as well, but takes special time for the main six, who seem to be Millie's very good friends. In The Pet Daycare, she suggests that she take more time for the main six, and later mentions that she does this already. She feels that Tank the tortoise should also have more time, but the boss of the pet caretaking business Millie is in declares that slower and smaller animals should have less time. At this, Millie decides to take care of the main six pets at her home, thus turning her home into a large pet playground. Fluttershy appreciates Millie's kindness and love for animals. Millie and Fluttershy are good friends, and sometimes Millie asks Fluttershy to take care of some of the animals on her list in exchange for the care of the main six ponies' pets. Despite of Rainbow Dash's protests, Millie constantly gives Fluttershy lessons on how to assert herself. Unfourtunately, Fluttershy benefits nothing from them, but se does get time with Millie and some of the animals that are with her at the moment. Strangely, when Fluttershy came up with a new assertive method, Millie still taught her these lessons, but maybe to get time with Fluttershy.