Seiko Ayase

Seiko Ayase She is a well-known spirit medium who also goes by the name Santa Dodoria and the grandmother of Momo Ayase. While performing her duties, Seiko provides support to Momo and her friends as they become involved with spirits, aliens, and other paranormal activities. Despite being a grandmother, Seiko has the appearance of a slender woman in her prime. Seiko possesses long snow-white hair that she generally ties up in a large top knot, wears red rectangular glasses, and can occasionally be seen smoking at times. On top of her youthful appearance, Seiko has been noted for her beauty that she claims others might go so far as to describe her as being bewitching. Due to this, many have mistaken her to be Momo's mother and leave them in shock once they learn her true relation to the girl. In terms of height, she is shown to stand no taller than her granddaughter.

When out in public, Seiko wears a yellow open large button cardigan that reveals her cross-strap top, a blue baseball jacket that has white sleeves with a symbol on the back, hoop earrings, and sandals. When at home, Seiko is shown to wear a white tank top, shorts, a beige haramaki, and light grey arm warmers with matching long socks.

Seiko has a phlegmatic personality and a highly uncouth manner of speech. At the same time, she is selfless and empathetic to help others in need if it's within her power, When involving herself with children, Seiko believes that, as an adult, she should be able to shoulder their burdens to allow them to be free to do what they want in life. Because of this, she felt saddened that she was unable to honor Jiji's wishes to help him keep the Evil Eye under control in order to spare the yokai from being exorcised. While willing to help others, Seiko is too proud to admit when she needs help herself or burden others with her problems. Seiko can also come off as being a bit immature Despite this and her unladylike way of speaking, Seiko can act polite if she feels that she has made a mistake that involves the well-being of others. This side of Seiko is seen as being rare and out of character to those who know her well. Though she claims that she has never been moved by emotion, Seiko subconsciously favors those who compliment her, such as her youthful appearance which she takes great pride in. Seiko has a passion for food, believing that it should not be taken lightly since "living begins with eating". As a cook who occasionally serves food for Momo and her acquittances, she finds it delightful to see a person who knows how to eat by filling up on the food she makes and even becomes motivated to make more to further satisfy their appetite. She was even willing to feed a restaurant full of Renjaku High School student at the cost of her entire paycheck. On the other hand, she dislikes picky eaters.