Kisaki Eri is the mother of Mouri Ran and the legally separated wife of Mouri Kogorou. Eri is a lawyer who often gets tangled in Mouri's cases, usually serving as an extra pair of eyes when it becomes time to investigate a crime. Although she does not like Mouri's attitude and personality (especially his drinking and nanpa habits), she still deeply loves and cares for him, often testing him to see if he still cares about her as well.

Eri and Mouri, like Shinichi and Ran and Heiji and Kazuha, had been best friends since childhood, falling in love in their teens. Ten years before the Detective Conan storyline starts, however, Mouri and Eri separated and took different paths in their lives. After seperating, Eri focused full time on her duties as a lawyer and has since become a highly respected (and feared) member of her profession.

Eri is considered incredibly attractive. Various men of different ages have pined for her, but she always turns them down, mostly due to her feelings for Mouri. She and Yukiko were considered the two most beautiful girls at Teitan High School back when they were students. However, even though the result ended in a tie, the two remained very close friends, often letting little Shinichi and Ran play together and have playdates. Shinichi remembers often how Eri would give him a big scolding for starting trouble.

Eri's personality suits her occupation as a lawyer. She is often very questioning, and gets herself involved in the investigation of cases along with Mouri, much to his chagrin. She has a cat, a Russian Blue named "Goro," whom she cares for very deeply. Eri is also very close friends with her secretary, Kuriyama Midori.

Eri is highly intelligent and has a sharp eye for details, and is also a skilled judoka, taught by Mouri himself. She has proven on more than one occasion that she can lend a big helping hand in cases, and her deductions are almost always accurate. Ran often goes to Eri for advice, especially on Ran's relationship with Shinichi. Eri has often half jokingly said that her best advice for Ran is to never get involved with a detective.

(Source: Detective Conan Wiki)