Yamabuki is shown to be mature, caring and kind-hearted. She loves her son, Riki, however, when the pup grows up, Yamabuki tells him that they can't be together anymore,e and that he has to start living on his own, like his siblings.
Ginga Densetsu Riki
A few years ago, an elderly woman bought Yamabuki to keep her company, as her husband died and she had no children. The old woman loved Yamabuki very much. However, she turned ill from age and had to give Yamabuki to her brother's family. While staying with the Bizen family, Yamabuki mates with Shiro and gives birth to 5 puppies.
All puppies except little Riki are taken away to new homes. Yamabuki is very caring towards Riki, but also tells him to be stronger as he is a male. She tells him that his father is the legendary bear hound, Shiro.
Yamabuki is eventually separated from Riki in a few months when her original owner gets better and Yamabuki returns to live with her. Still, Riki returned to see her every day despite the long distance. This likely made Yamabuki very happy as it showed that her son is strong after all.