My best guess is that when he was only alive in curse seal tattoos, he absorbed the feelings of the people he was attached to through their physiology.
I think weve all noticed the change in heart that Orochimaru has expressed after his revival. Whats causing him to change so much? Does he now indirectly know that hes the final sannin alive? Whats he gonna do after Sasuke gets his answer from Hashirama? I wonder if theyll become partners instead of student and mentor or possibly Oro working for Sasuke. Hes basically doing stuff for him now
