I feel like real motivation is sometimes lost in fantasy stories. But giving a real human element to the responsibility and guilt is more than just "i am strong so i must protect."
How the hell did they find someone as big if not bigger than Julius, thought Julius was supposed to be a monster of modern medicine. Also the masked man has a pretty similar build to Agito, maybe another clone time?
I hope they hold him to "oath" he made at the beginning of the trial to tell only the truth.
Fucker deserves to go through the same pain he put Leslie in