Keiko was born in Lipun, but left at an early age for Amber. Her exceptional skill with magic soon landed her a position working for Nanami in Amber City, and she rose to become the head of the Sorcery Division in a fairly short time.
During the Annadil Crisis she worked closely with Shaft and Ramon on several missions, and became romantically involved with Ramon near the end of the Crisis. They married soon after. She was also revealed during this time to carry the Blood of Ember in her, and was officially adopted by Corrine after she walked the Fire Pattern.
Keiko was to have given birth to twin daughters, but an assassination attempt near the end of her pregnancy resulted in the death of one of them. The other, Motoko, was sickly in her early years, but soon grew strong and healthy.
Currently, she serves as Amber's Court Mage. Of late she has had difficulty with a sorcerer of Leng, The Great Lo, but his recent death at the hands of Nausicaa and others has solved that problem for the moment.
She is known to dislike Moonshade, due to Moonshade's hitting on her husband. To quote Keiko's comment to her daughter, Motoko, "Hello, daughter. Have you met Ota's other daughter, the giant slut?" It is generally believed that she is not very pleased with Moonshade having become Motoko's new Sword.
She very recently had a third daughter, Nanami Minor.