Cassian Rosier: what makes him dangerous? [Episodes 3–4 spoilers]

Cassian arrives with a family arrangement behind him, and then steps into Harry and Draconia's world at Hogwarts. What unsettles you most: Cassian himself, the power of his family, or how much control Lucius has over Draconia's future? Is there a moment where his charm feels more like a warning? Pick one scene or line and tell us why. Keep any predictions clearly labeled as theories, not spoilers for unreleased episodes.