[ Perhaps Set is unbothered by Byleth's lack of affect, because several members of the Ennead ( Tefnut, Bastet, Sekhmet, himself, Horus, even Khnum —— ) wore masks that obscured their faces from sight. Certainly, their mouths were visible to articulate and express, but there was a marked elusiveness to their dealings because their personal marks of divinity obscured them. He has lived among masked gods, and while Set will never claim to be able to easily read someone — for too often, he has entrusted himself to the exterior presentation of self — he would never think that Byleth's lack of affect meant he was unfeeling.

To hear that not just one individual, but many, have told him otherwise offends him on Byleth's behalf. Set bristles with indignation, nose wrinkling as he hears what Byleth says. That he has been told he is heartless, without emotion. Emptied, and why? Because his heart has been bound to a goddess's own? ]

Do you actually wish that to be the way of things?

[ The question comes off a little aggressive, hot-tempered and testy. ]

You do not have to be perceived in such a way, whether your face remains flat as a wall or not. You can [ still escape such a fate ] tell them who you are, you know.