Both sent by Master Eraqus to seek out Master Xehanort and his cohort, Terra and Ven are the main protagonists of the Kingdom Hearts prequel, "Birth by Sleep". Terra bears a striking ressemblance to Todomarishi Shinsen from Kindom Hearts II Final Mix just as Ven does to Roxas.
Alright, readers who keep sending this in can please stop now! Terra is cosplayed by Courto and Ven is cosplayed by Akusesu from Deviant Art; photographed by Tony Quan. Really wonderful work! Great job guys!