If it’s anything like Xenogears or Xenoblade, there’s a demonic godlike creature resting in the soul or consciousness of Rex.
Now if the story starts out with Rex doing some sort of task involving a long haired samurai-type who becomes the wiseman samurai of the party, then has an Imperial army land and destroy the village, then he gets his hands on his super-weapon to fight them off, we can reasonably suggest the story will be another one based on Xenogears. Especially if Rex has some kind of amnesia, and sees the (earlier) love of his life slaughtered before his eyes.
Last edited by Jumpin - on 27 November 2017I describe myself as a little dose of toxic masculinity.