i'm not sure if this has already been on the forums but the kingdom hearts 2 secret ending isn't based on the psp title because the ending said "it all began with...birth by sleep"meaning that it continued on from birth by sleep.this means master xehanort from the secret ending should be the final boss for kingdom hearts 3 and in some point in the game you should meet terra.looking at it from this point Terra and the other 2 must still be chasing after master Aero (xehanort)