Cologne (可崘, Kě Lún?, or コロン Koron) is the great-grandmother of Shampoo and upon Shampoo's return to Japan, she moved to Japan with her and opened the Cat Cafe.
Cologne is a master martial artist and knows many techniques that had been lost to the ages. She is a constant source of trouble for Ranma, because she knows how strong he is and that the would make an excellent fiance for her great-granddaughter. But despite causing so many problems for Ranma, she honestly likes him and has helped him to become a much more talented martial artist teaching he and Ryoga such techniques as the Bakusai Tenketsu, Kachu Tenshin Amaguirken and the Hiryu Shoten Ha. She also helps out Ranma in Dire need
Cologne also had a relationship with Happosai in the past. He visited her village in China decades ago and fell in love with her. Of course Cologne was much more attractive then, but she did not fall for Happosai's lustful charms. The two seniors have now become rivals and can not stand each other.
Cologne can be broken down to "approve" and "rugged mountain-place" which has no real meaning. The real pun in Cologne's name though, is that all the Chinese characters are named after beauty products, such as Mousse and Shampoo.