Mata-Yadh is a "Fledgeling Behemoth" a phrase which here means "Pretty damn powerful, but possibly beatable by a starting Circle if they prepare, co-ordinate, and at least all have offensive Excellencies". It's interesting, and I've just realised in the game I'm playing my Circle (of 5 Essence 2 Solars, including a Dawn and an Ebon Shadow Night, but no-one else particularly focused) killed a reskinned version of this (sans rider).

The Doppleganger is a pretty scary, at least insofar as it has the potential to keep up its ruse for at least a conversation with a Solar. They're pretty close to the generic idea people have of them, but this flavour is undead and has a vendetta. It has an Eclipse charm that lets you steal motes.

I'm mostly rating this 5/5 because of Mata-Yadh being a great example of how to make a threat for your Circle that they'll have to work smart and hard to deal with, and because I was pleasantly surprised by the Doppleganger; to be honest, I'm also a bit of a sucker for anything that I can just "yoink" and this includes the Eclipse Charm.