Nodoka is Ranma Saotome's mother and Genma's wife. She is a gentle, attractive woman, who very closely resembles Ranma's female form, noticeable after Nabiki comments on how similar they look during Nodoka's first visit to the Tendos. She always carries around a fairly large bundle, which contains the family katana.
Before departing on their training journey, the only way Nodoka agreed to let Genma take Ranma from her was for her husband to promise her that he would train Ranma to be "a man among men." If Genma were to fail in this regard, both he and Ranma would commit seppuku. Nodoka agreed to this and also that she would be the kaishakunin for her husband and son - hence the need to always carry the katana. She is not particularly skilled with the sword, though. She has, upon drawing it, accidentally thrown it into the air, nearly impaling Ranma, who was off-screen.
Because of this promise, Genma and Ranma are terrified of showing their true forms to Nodoka and for her to find out about their curses, although Genma is more afraid than Ranma. To prevent her from finding out, they hide in their cursed forms, with Ranma taking the alias of "Ranko" and pretending to be Akane's cousin from the countryside, and Genma assuming the identity of "Mr. Panda" and pretending to be Ranko's pet. Late in the manga, Nodoka learns the truth and she decides she won't force them to commit seppuku so long as Ranma stays interested in girls and continues to fight like a "man amongst men."
After this, Genma and Ranma live for some time in her house, until it is destroyed (in an unshown scene) by Shampoo, Ukyo and Kodachi, who are fighting over what they think is an engagement ring. She and her family then move back in with the Tendos.
Nodoka wants nothing more than to see her son, to whom she has not spoken since he was six years old. She is not the only one who has been affected by the deal, though. Ranma has tried on numerous occasions to talk to her as a man, but Genma repeatedly foiled his efforts. For Nodoka, her glimpses of Ranma as a male have been fleeting at best, usually because he was pursuing some other objective at the time, or attempting to escape her.
When she met Akane, she quickly approved of her and offered to help with her cooking skills so that she could make a better wife for her son. She also dotes on "Ranko" and has aided her to similar ends. In her most notable incident of the sort, she took Ranko shopping to find her more suitable feminine clothing, including a bra, something Ranma would never normally wear. But the existence of Ranko's identity created a strange situation for Ranma when Ryu Kumon arrived. Posing as Ranma, the rival martial artist had sought out Nodoka for his own ends. She was initially convinced as to the imposter's identity as her son, but became suspicious after seeing him with Akane and was eventually told the truth.
Nodoka, while kind and slightly old fashioned, has a very strange set of principles. She seems to despise perverts, but is willing to allow and even encourage Ranma to perform perverted acts such as peeping on girls, play with women's underwear and even have him spy on Akane while she takes a bath. It is explained, however, that she sees this as the way her son can "prove" his manliness. Her actual view of a true epitome of masculinity seems to lie much closer to the savage, imposing, independent and semi-militaristic Ryu Kumon than to Happosai.
In contrast to her enthusiasm to see Ranma, she has shown an often comical lack of concern for her husband. Going as far as to not notice him right next to her, and making almost no response at all when Ryu Kumon said he was dead.
Nodoka is dedicated to the seppuku contract Genma signed before he and Ranma left, and is more than willing to follow it if she believes she has to. One encounter with Ranma, which had Ranma dressed in girl's clothing thanks to Happosai, had her immediately get ready to perform the ceremony, though she was knocked out and apparently dismissed her memories of it as a dream after waking. She still retains the seppuku contract, and considers it valid, even after being reunited with Ranma and Genma. When the Saotomes moved back to Nodoka's house and Ranma was depressed at having left Akane, she declared that Ranma's behavior wasn't manly and would have drawn her sword had not Genma intervened.