This is revisiting conjecture #1: I keep seeing hints of it -
(1) Ri Ta says that he was warm in her memory, when he placed medicine on her forehead, as warm as he is now with human temperature. This is a big hint to me, that being kind/feeling something close to love is what makes him human.
(2) He is calm whenever he colours pictures.In particular, they mentioned Jeju Islands and the woods, which always made him think of her. Yet another obvious evidence!
Has anyone picked out anymore things?