Innocent, naive, and energetic. She is very expressive and honest with her emotions, cheering with her whole body when happy, but she also shows a childlike side, bursting into tears easily when she fears being excluded by her friends or when she gets scolded. Since she doesn't go to school, she seems to lack general common sense. She absolutely loves sweet snacks like gelatin and sugar. She shatters easily if she falls from a height or hits a hard object. She is close with Book, Bubble, Match, and Pencil.

Self-centered and highly competitive, she is the leader of the group consisting of Ruby, Bubble, and Match. She often tries to control the group or ignores their efforts. While she is close with Ruby and Bubble, she is extremely close with Match.

She shows a dual personality, being kind to those she likes while thoroughly excluding and ignoring others. She is especially close with Pencil; Match calls Pencil by the nickname "Pence-Pence" and hates it when others use that name. She has a somewhat selfish side. She dyes her hair often. She is reasonably close with Ruby and reconciled with Bubble after a fight.

Since she is a bubble, she pops even if poked slightly. She is very kind-hearted and used to have a weak will, though she has grown more assertive over time. Her friends sometimes perceive her as a fool who can't even count to three. she gets along well with Ruby; her relationship with Pencil has soured compared to the past, and she is back on good terms with Match after their fight.