User blog comment:ImperiexSeed/Supernatural Mysteries/@comment-3481504-20120516033047/@comment-1509826-20120627185453

Creation is a bit vague isn't it, creation of what? Heaven? Leviathans? Earth? Angels? Man? Beasts? Other? The point is theres a lot of creations, so its possible that Castiel ment he was the scribe for the creations that occured after the Leviathans.