Ok like I said at another thread if anyone saw it I just thought of the weirdest thing that could possibly kick me off this site for being so weird and dumb but I will post it anyways. Ok what I think Birth by Sleep means is that Sora, Riku, and Kairi were sort of born by terra aqua and ven falling into a deep sleep, Ok I think that the knights fell into a deep sleep after the battle with the DS and the U.E.M.Before the DS and the U.E.M were defeated they put the knights in a deep sleep. Then they lost all their memories except for Terra remembering only what Xehanort ( DS or the U.E.M I really dont know)did to the knights making them fall into a deep and making his friends forget their memories.Anyway when they were asleep sorry for the lack of details but sora riku and kairi were somehow created but just normally nothing special about them and that is why they inherit the keyblades( with the exception of sora in riku's place). As for Terra he woke up where he was when you find him in fm+ and for Aqua and Ven they were given kinda fake memories about having Sora and a normal life with no keyblades or anything so they are Sora's parents. As for Riku and Kairi's parents they could've been knights too and the same thing happened to them. Who knows, because nothing has been known of Riku and Kairi's parents. So there it is sorry if it is boring and if there is know specifics or anything it was just a thing that popped up in my head and became a big thought at the end so I just posted it.