Soitsu, Doitsu, Koitsu, and Aitsu are characters from the Parodius Series. They are seen as little stick men flying on paper airplanes. They are also monsters in the Yu-Gi-Oh! trading card game whose full power cannot be utilized unless they're played in pairs. 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). It also makes a cameos: A book as the game Tokimeki Memorial: Forever with you (1995), as an unlockable character in Speed King NEO KOBE 2045 (1996), in the game Super Bishi Bashi Champ (1998) and in the two castlevania games: Castlevania: Portrait of Ruin (2006) and Castlevania: Harmony of Despair (2010).
Weapon set
Gokujo Parodius
S= Speed Up
M= Homing Missile
D= Round Shot
L= Wave
O= Grade Up
?= Aura
Sexy Parodius
S= Speed Up
M= Strong Missile
D= Round Shot
L= Wave
O= Grade Up
?= Aura