Sugar appears to be a ten-years old girl, but is actually much older, being 22. This halt in aging is due to the effects of her Devil Fruit. During the takeover of Dressrosa, she wore a light-colored dress with a hood having bear-like ears.
While she is in the underground world, she wears a dark-colored hooded robe with bear-like ears, a monocle shaped and worn like an eyepatch, and a small crown, as well as sandals.
She has aquamarine hair, a pink monocle with a purple covering, and a white dress with light blue polka dots and open-toed sandals.
She is loyal to Doflamingo since she helped him take over the kingdom of Dressrosa. She is shown to be cruel, turning many citizens into toys and subjugating them into slavery while making them forgotten by anyone who knew them. She does take great pride in what she did as she was angry when the toys returned to their original forms and she intended to exact her revenge.
She has shown signs of childish behavior, as demonstrated when she ran around the palace, looking for Doflamingo, after he had already left for Punk Hazard.
Sugar appears to be fairly indifferent about the events that happen around her, as she showed no reaction when Baby 5 attacked Doflamingo. However, she became utterly terrified after she forced Usopp to eat the extra-spicy Tatababasco-laced grape, when he made a horrifying visage of pain that scared Sugar into unconsciousness. As a result of this, she became terrified of long noses and things that looked like long noses, freaking out when a long nosed soldier offered her some sausage. She likewise showcases a rather scary anger since all the work she's done over the years was undone thanks to the Straw Hats (though ironically she never takes into account that this was also due to her own actions. Trébol had managed to beat Usopp easily. But in trying to make Usopp suffer more, she unwittingly caused her own trauma and the undoing of Doflamingo's secret).
She has a fondness for grapes, which are apparently her favorite food. She often eats them off her fingers. She is shown to be quite rude to Trébol, despite the latter being in charge of her protection.
She seems to be annoyed when people consider her to be weak due to her child-like appearance, to the point where she (literally) drops everything to show off her strength.
Despite her child-like physique and having Trébol as her bodyguard, Sugar is quite formidable in terms of speed and agility, as seen when she countered a number of attacking Tontatta Dwarves, who are fast enough that normal Humans cannot see them. However, she has a rather weak constitution, as she freaked out and lost consciousness when Usopp made a horrifying visage of pain and anguish after being force-fed the Tatababasco-laced grape. This became her Achilles's heel, as whenever she sees anything that reminds her of Usopp's long nose, she would suffer a traumatic attack that could cause her to faint.