"From what I've heard about Faust from the usurper is true, and that she seeks to attack Equestria, then she is already far from the kind and gentle pony Starswirl always described her as. I know she's powerful, and I know that she likely won't look kindly on us changelings. If you cannot defeat Faust, more than just Equestria is doomed, which is the only reason we are aiding you."