Millie and Cas (her sire)
Name: Something obnoxiously long and Italian. Millie would come up with a far better nickname that everyone would use because fuck you Cas your names are stupid you're not allowed to make decisions
General Appearance: Skintone somewhere between the two, crazy big red eyes, Cas' big nose, dark hair. Would end up rather tall.
Personality: SMARMY LITTLE SHIT. Knows that they're better than you and willing to prove it at every occasion. Has enough decency to at least act polite and civil so long as they feel it's useful, but heaven help the person who pisses them off.
Special Talents: Fluent in Italian, musically talented
Who they like better: Cas
Who they take after more: Mix of them both
Personal Head canon: Cas not only lets them get away with things, he actively tells them the opposite of what Millie wants to piss them off.