It is a reference to the chinese/japanese
superstition: 'Kuwabara' literally means "mullberry field" in Japanese, and according to legend mulberry trees cannot be struck by lightning. Saying "Kuwabara, Kuwabara" is supposed to protect the speaker from lightning. In the game
metal gear solid 3:snake eater, Volgin chants this on the bridge after the end of the virtous mission. and ironicaly enough he dies by a
lightning bolt at the end of the game.