>>36138872It's weird, it just meant that Mouse can have different shapes and forms, and she can transform into them, which is what Satan is known from. Right now, Mouse uses it as an excuse for more costumes, and Merry put it as a reference and to explain that, there's a Satan in every single universe, and she shouldn't leave her spot as such. Someone made this chart to explain the Canon Mouse, or the Mouse from the current Mythos Storyline
although it needs some updates 