This is Shampoo, an amazon from China.  When she fought Girl type Ranma and lost she gave her the "kiss of death".  She then followed Ranma and Genma back to Japan.  There she was defeated by Boy type Ranma.  According to Amazon law she now has to marry him.  She also has a curse, whenever doused with cold water she becomes a cat. Unfortunatly Ranma is afraid of cats.  She is a good martial artist and will use all sorts of tricks to get to marry Ranma.