Yum Yum

About
"Yum-Yum" does not appear to have any extraordinary abilities, so she does not play as active a role in solving the mysteries, but is still a major character in the series. She is also Siamese, and had a troubled past. Her history is fully explained in The Cat Who Ate Danish Modern, but it can be summed up rather briefly. Qwilleran got Yum-Yum as a kitten from the Taits, rich folk who did not treat Yum-Yum properly and did not even truly decide on her name. Mr. Tait, a jade collector, named her Yu after a variety of jade, while Mrs. Tait, whose family originates from Aarhus, Denmark calls her Freya, after the Norse goddess of love.

Adoption
Qwilleran adopted her partially because he could not stand her circumstances (explained in The Cat Who Ate Danish Modern) and partially because, after consulting an expert, Qwilleran realized Koko needed someone to keep him company. Yum-Yum is named after a character in the opera The Mikado by Gilbert and Sullivan who is also the ward of a man named Ko-Ko.