Kyuusuke Sarashina

attends elementary school with Chibiusa. He is targeted by the Amazoness Quartet in Episode 155. He is a friend of Chibiusa and known to be very athletic, but also sarcastic. In the episode he is targeted by Amazoness JunJun, he is attempting to overcome his fear of the vault, the only portion of the athletic relay he has trouble with. JunJun, in order to see his dream mirror, scares him into leaping over the vault, effectively giving Kyūsuke the confidence to continue in the athletic competition (after Sailor Moon and Sailor Chibi Moon save him from JunJun).

He also plays a significant role in a later episode, when Chibiusa befriends a boy named Hiroki, who is trying to build a flying machine. While Kyūsuke initially seems resentful of Hiroki and how impressed Chibiusa is with Hiroki's dream, Kyūsuke ends up being the one to encourage Hiroki continue building the flying machine after multiple failed attempts. He tells Hiroki that some dreams must be achieved with the help of another person and that a dream is no less beautiful as a result. With Kyūsuke's help, Hiroki completes the flying machine when he realizes that alone he lacked the power and endurance to keep the machine in the air, but with Kyūsuke helping him pedal, it would take flight.

(Source: Wikipedia)