Kotake Sakura is Maruko's paternal grandmother, married to Tomozou Sakura. She is the mother of Hiroshi Sakura and mother-in-law to Sumire Sakura, fulfilling the grandmother role for Maruko and her older sister Sakiko.

Her appearance features grey hair usually styled in a bun secured by a pink pin. She wears round glasses and is often seen in a maroon kimono, both at home and outdoors. In summer, she sometimes wears a short-sleeved purple dress with a collar. Dimples appear on both cheeks. Flashbacks reveal she was considered a beauty during her youth.

She demonstrates kindness and warmth, particularly when offering health advice or recommending foods during illnesses. Kotake practices prudent habits rooted in traditional wisdom, such as insisting mold or insects in food are beneficial and should be consumed, not discarded. She habitually hoards practical items like bottle caps, believing they might prove useful later.

Her skills include proficiency in traditional Japanese games like cat's cradle, which she teaches to Maruko. Kotake maintains photo albums created with Maruko, considering them prized possessions. She admires the celebrity Shinobu Oshizaki.

Regarding culinary preferences, Kotake favors sweet natto, yokan, and sekihan. She provides practical guidance within her family relationships.