I had to think about this for Chisaki, who'd be afraid of the older kids at the home beating her up!

My thought was they can split into multiple bodies kinda but it's more like there's tendrils of shadow linking their feet and they have to stay together. It's more like a frightening mass that links together here and there, fluidly and creepily? So if she feared, like, a squad of mage soldiers attacking them, it could do that.