Shampoo's age is 16 and comes from China. She is part of an Amazon tribe there. She is first introduced when Ranma and Genma took a training trip there and were being toured by a guide. Eventually they came upon a place where a contest was being held in which the native tribe has fights to see who is the strongest. The winner of the contest gets the honor of enjoying a prize which consists of a large feast. Ranma and Genma were of course very hungry from touring and unsuspectingly went to the table with the food for the feast and ate while Shampoo was busy fighting. Shampoo won and then looked over only to see Ranma (who was a girl at the time)and Genma eating the prize and so she became very mad. Ranma then finds out what he has done and finds out that the winner of the contest gets the prize!!! So in order to ablige by the rules he challenges Shampoo! After a short battle, Ranma winds up winning. But then Shampoo gets up and kisses Ranma. He finds out what she just gave him was the kiss of death. The kiss of death was given because by tradition if an outsider of the tribe wins the contest, the only way to revenge that is to give the kiss of death. What the kiss of death is, the guide who was with them explains, is that it is a promise to find and kill the person who dishonored her and her tribe!!! Ranma and Genma after hearing this manages to escape to China and went back home to Japan after many times almost being caught by Shampoo. And they thought that they were safe...
One day Ranma, Akane and P chan were eating at a restaurant. And then as they were watching T.V (which coincedently had a story about the amazon tribe in China) someone broke through the side wall of the restaurant. Shampoo!! (She has a habbit of making her own doors) She saw Ranma who was a girl at the time, and immediatly began to attack him. After Ranma hid, Akane was able to lose her or so they thought. Thats when Ranma explained the whole story about Shampoo to Akane. When Ranma came home though a surprise awaited him. Shampoo was over!! Ranma was a guy this time though and Shampoo never saw him as a guy. When she heard the name Ranma she looked at him and didn't understand why he was a guy. Shampoo not understanding yelled at Akane and accused her of hiding female Ranma and so began to attack Akane. But Ranma defended her and in doing so broke Shampoo's weapon in half and half of it landed on top of Shampoo's head and knocked her out. She then got up, looked and found Ranma and as Ranma was trying to find a way out Ryouga came in a chiverlously said to Ranma "Be a man and take your kiss of death" and pushed him into her. And thats when she kissed him and proclaims her love to him. It is later found out by a book about Amazon law shampoo handed out that by tradition if a male defeats her in combat she must marry that male.
So now Shampoo loves Ranma and always tries to plot ways to have him fall in love with her and with the help of her meddeling great-grandmother Cologne. But she is also still angry at girl-type-Ranma since she lost to her and didn't kill her. Later on though she finds out the both Ranma's are the same person and is no longer mad unlike Kuno. But before she accepted this fact she, by tradition had to retrain in order to beat girl-type-Ranma and she happened to be training in Jusenkyo. Needless to say while she trained she also fell into a spring. She fell into the Spring of drowned cat and now takes the form of a cat anytime she is splashed with cold water. Shampoo is very strong and athletic and when she sets her mind up to something she really tries to accomplish it. Alot of how everything began between Shampoo and Ranma and most of what I described takes