[demon of darkness]

ya know in chain of memories when namine said that she could lock xehanort's heartless in riku's heart and keep him from escaping, but riku refused. well what if master xehanort posses terra and terra decides to keep him locked in his heart. this could have caused terra to lose his memory and cause him to look like the current xehanort. therefore birth by sleep means master xehanort was put to sleep in terra and gave birth to young xehanort