Mayako was an anime only character. She was older lady who owned a large house, and was notorious for being rude to those who acted kindly toward her. Rumour had it that she was suspicious of anyone who tried to get close to her, as she assumed they wanted her property; it was true that some thugs were trying to harass her into selling her house.
In truth, she was not mean, and she took first Diana, and later Chibiusa, into her house and cooked them some of her delicious food, her speciality being her stew. She was a target of Hawk's Eye, who chased the thugs off, but then was offended when Mayako spurned him, as she did to everyone who acted unexpectedly kind toward her. After he looked into her Dream Mirror and left, and after Super Sailor Moon and Super Sailor Chibi Moon defeated his Lemures Autobiko, she was approached by Ichirou Ohno.
It turned out he was her former lover who had left her and their dream of opening a restaurant to study in France, thinking himself to good too open a restaurant in Mayako's house. It had been twenty years since they had last seen one another, but Ichirou had realised that he had been selfish and that his food, while critically acclaimed, did not taste as good to him as her stew. The two made up and opened a restuarant in Mayako's house as she had always planned - Rokuten Restaurant.
(Source: Project WikiMoon)
