Seiko Ayase

Seiko is blunt, irreverent, confident, and fond of speaking to teenagers with very little formality. She regularly teases Momo and Okarun, mocks overly dramatic behavior, and approaches supernatural crises with the composure of someone who has spent years handling spirits professionally.

Her rough language conceals a strong sense of responsibility. Seiko believes adults should shoulder burdens so that children have the freedom to live their own lives, and she repeatedly opens her home to people who need protection. Rather than accepting money from Okarun for helping him, she tells him to repay the kindness by helping someone else in trouble.

Food is another expression of that caretaking instinct. Seiko regularly prepares large meals for Momo's expanding group of friends and allies, turning the Ayase house into an informal gathering point after dangerous encounters. Her fondness for people with healthy appetites fits this habit.

Seiko is an accomplished spirit medium with extensive knowledge of yokai, curses, chi, sacred boundaries, and exorcism. Her strongest spiritual techniques rely heavily on the power of local gods, meaning she is especially formidable within territory protected by deities with whom she has established a relationship.

Barrier casting is one of her specialties. Seiko can establish boundaries around locations such as her home and use talismans or sacred geometry to trap, weaken, or exorcise hostile spiritual beings. Her barriers become particularly dangerous when opponents are deliberately lured into their effective range.

She is also physically formidable. Seiko fights with a baseball bat wrapped in spiritual inscriptions and can combine ordinary striking ability with supernatural reinforcement. Her reflexes and awareness let her engage entities that ordinary humans cannot even perceive.

Seiko understands chi well enough to teach Momo how to focus her psychic ability and later instruct other characters in controlling spiritual energy. Her greatest limitation is geographical: many of her strongest techniques depend upon borrowed divine power and cannot simply be reproduced anywhere.

Seiko becomes directly involved after Okarun is cursed by Turbo Granny. She protects him inside her spiritual territory, explains the mechanics of the curse, and organizes a plan that allows Momo and Okarun to challenge the yokai under conditions where she can assist them.

After Turbo Granny's defeat, Seiko remains the group's primary supernatural expert. She explains why hostile spirits form, identifies paranormal phenomena, performs rituals, and repeatedly provides the practical framework needed before Momo's group can confront a threat safely.

During the Cursed House and Evil Eye incidents, Seiko becomes central again through her connection to Manjirou, whom she previously trained. Her knowledge helps separate the different forces operating around Jiji and his village.

Later manga arcs expand Seiko's own activities beyond supervising the younger cast. She becomes directly involved in investigations concerning powerful yokai, ancient spiritual techniques, and enemies specifically interested in stealing supernatural powers.

Momo Ayase is Seiko's granddaughter and only established close family member. Seiko raised her and taught her the foundations of spiritual practice, although Momo once resented being embarrassed by rituals she did not understand.

Ken Takakura becomes one of Seiko's regular houseguests after she helps contain the curse placed on him. Seiko gradually treats him as part of Momo's extended family.

Turbo Granny begins as Seiko's supernatural enemy but later shares the Ayase home in a maneki-neko body. Their argumentative companionship develops into a surprisingly comfortable relationship.

Manjirou is Seiko's pupil and a fellow spirit medium. She trusts him to assist Momo's group when supernatural trouble emerges in Byakuja Village.

Jin Enjouji receives Seiko's protection and spiritual guidance after becoming connected to the Evil Eye.

Aira Shiratori becomes another young supernatural fighter whom Seiko allows into the group's increasingly crowded household.