Soitsu, Doitsu, Koitsu, and Aitsu

Soitsu, Doitsu, Koitsu, and Aitsu are characters from the Parodius Series. They are little stick men flying on paper airplanes. Their names are commonly used in Japanese slang terms to refer to people one does not know (Doitsu = who, Koitsu = this guy, Soitsu = that guy - far from the speaker, but near to the listener -, and Aitsu = that guy - far from both chatters). They are represented by four colors: Red, Green, Blue, and Yellow, however it is unknown which stick man is which.

Trivia

 * All four stick men make cameo appearances in the Yu-gi-oh trading card game, just like numerous Gradius crafts. However, they are rendered useless unless they are played together in pairs.