Minako Sasebo... the girl who stole Ginji Kusunagi from me! I'll teach you what it's like to have the one you love ripped away from you! I'll start by taking away something dear to you!! Just you wait and see, Minako Sasebo. *laughs*
~ Coach IIsa planning her revenge
 IIsa Kyoko or better known as Coach IIsa, is the main villain in Volume 10 of Tuxedo Gin.

At the beginning, IIsa Kyoko was seen being yelled at by Suramura. She was told to either find a penguin trick that would amuse him or that she would be fired. The next day, she convinced the penguins to perform a whirlpool trick. However, Suramura attempted to drain the water so that IIsa would die by getting her leg stuck in the drain, only to get saved by them. Afterwards, Ginji led her to his old room so she would rest. IIsa looked into his photos, which were taken back when he was still a human. IIsa immediately developed an obsessive crush on him (not knowing that he's a penguin). When she first became friends with Minako, IIsa felt like she was her first friend ever since she moved into town. When IIsa told Minako about Ginji, she told her that he died from the motercycle accident and that she never heard of him.

However, IIsa eventually realized that Minako lied and that Ginji was alive, as well as having a crush on him. Enraged from it all, IIsa decided to have her revenge against her. At the Christmas Party, IIsa gave Minako a swimsuit that matched hers; however, the difference was that Minako's straps were actually made of paper. She planned for her to get splashed during the competition so that her swimsuit would fall off completely, thus being humiliated by everyone. In the kitchen, after Mike told Ginji about her ruse, IIsa chased and tried to kill them with a butcher's knife, only to jump into the sewers instead. During the competition, when Minako was about to cross the finish line without even touching water, IIsa decided to take matters into her own hands and to get there herself. She even claimed that they were going to cross the finish line together as "friends" As she was about to grab Minako, Gin dived in and both of the girls fell through the waterslide. Upon the pool, it turned out that IIsa was the one wearing the paper swimsuit the whole time (which fell off) and ended up getting humiliated herself.