Personality-wise, Sis appears to be a typical young girl. She is friendly, but she can be bossy and she likes to tease her brother Skippy. Judging by one scene, she may harbor a slight crush on Robin Hood, as she mentions that he is handsome, "just like his reward posters" upon seeing him in person.
Sis is a white colored rabbit. She wears a long red dress with pink bloomers, and her ears are tied with a large pink hair bow.
She seems to be taller and skinnier than Skippy and her other siblings, possibly making her the firstborn. In her cameo appearance of Mickey's Christmas Carol, her dress is violet colored.
Sis plays a fairly minor role in the film, having a major role in only one or two scenes. The rest of her appearances are cameos.
She is seen with her family at Skippy's birthday party. Like the rest of them, she is angry when the Sheriff of Nottingham steals Skippy's birthday present, but cheers up with Robin Hood comes with his own present for him. She takes a moment to tease Skippy about Robin's hat is too big, before being scolded by her mother and to have her little sister repeat the scolding.
She then goes with Skippy, Tagalong, and their friend, Toby, to go test out Skippy's new bow and arrow. She warns him that he is shooting the arrow too high, and watches him do so into Prince John's courtyard. When Maid Marian invites them in, Sis notes that the former is very nice and encourages Toby and Tagalong to come. She watches as Skippy role-plays Robin's rescue of Marian and laughs when Lady Kluck mimics Prince John and when Marian kisses Skippy.
She later has a few cameos throughout the rest of the film. She attends the archery tournament and is seeing cheering for the competitors. Later, she is shown during the song "The Phony King of England". After that, she is imprisoned alongside the rest of her family, for not paying taxes, and later escapes along with them (ducking and jumping to dodge arrows). She appears at the end as the newlywed Robin Hood and Maid Marian ride off to which she catches Marian's bouquet much to Tagalong's madness.