Thought it was weird too at first, but I guess you could think of the "ung" sounds she's been making as some kind of animal noise, so it's just an extension of that? idk
That's Miesa's defensive reaction. She's trying to make herself appear as harmless and pitiable as possible so Eric doesn't hurt her.
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I like how we are not rushing through Miesa's recovery from the King's abuse. Those stories that speedrun the healing process always feel hollow for some reason. I can't wait for the maids to be expelled. They cannot be let go fast enough.