Shampoo
Personality: sweet, affectionate as well as
hyper-
violent and a ruthless ice queen
Psychology: obsessive/homicidal
Curse: aqua-feline-lychanthropy
(turns into a cat when splashed with cold water)
While still touring China, Genma-panda and Ranma-chan stop at the village of Chinese Amazons. Being starved, they immediately start eating from a table piled with food. However, it turns out the food was first prize in the village martial arts championship. Shampoo is the victor and is outraged to find them eating it. Challenged, Ranma-chan fights and defeats Shampoo, who rises and gently places a kiss on Ranma-chan's face. However, this is not affection. Under Amazon law, any Amazon champion defeated by an outsider woman must seek out and kill the one that defeated her. The kiss is the traditional kiss of death. Ranma and Genma immediately flee with Shampoo in hot pursuit.
Years later at the Tendo's, Shampoo tracts them down and attacks Ranma-chan, only to be defeated again. Attacking again later, Ranma-chan is splashed with hot water during the fight and Shampoo is defeated this time by Ranma-kun. Shampoo rises and kisses Ranma-kun, only this time it is with affection. It turns out that under Amazon law, if any Amazon is defeated by a man, she must marry him. Thus, Ranma has managed to catch another finance (number three). For the next few episodes, Shampoo doesn't realize Ranma's secret and tends to attack Ranma-chan whenever she sees her.
Shampoo constantly pursues Ranma and with the help of Cologne hatches various schemes to ensnare him. She also will take any occasion to try to off Akane if she gets the chance to get Ranma for herself.