Tamako is Nekota's younger relative.
Tamako has distinct facial features that make her seem intimidating—her long irises and distinctly pointed mouth which gives her a catlike appearance. She has light colored hair partially tied-up with short trimmed bangs.
Tamako is very expressive about her feelings. She does not know how to speak but makes her feelings clear through her expression and the tone of the nonsense words she says—with Inui, Taka, Kirin and Ryuuichi all knowing when she insults them.
Tamako is brought to the Babysitting Club by Nekota, who has to look after her for the day.
After Inui says she looks terrifying, she insults him, nobody besides Inui really caring. When Kotarou defends her for her terrifying appearance, she tries to monopolise him and becomes angry at Taka and Kirin for trying to take Kotarou back from her. Nekota realises she has developed a crush on Kotarou, but after explaining that means Tamako loves Kotarou, Kotarou declares Ryuuichi the one he loves most, leading Tamako to insult Ryuuichi as well.