Who are Sora and Riku

Characters from the Kingdom Hearts Games. Duhh <3
Sora is the one with the upward spikey hair and Riku was the one with the silver or gray down hair. They were childhood friends along with Kairi, Sora and Riku were always in competition with one another the way that brothers are, Riku probably being the eldest brother, and Sora the younger brother