He’s your current employer, and you live in his house.
Not a red flag. Not for you at least. As the person in the higher class, he is the one with the most to lose. For you, there is nowhere to go but up.
He lies to you about who he is when you first meet.
Not a red flag. This is called keeping the mystery alive, and he is smart to make a habit of it early on.
He accuses you of putting a spell on his horse.
Not a red flag. Insisting that the person you like has used dark magic is actually a very common method of flirting. All the kids/ grown men are doing it. Other versions of this technique include accusing the person you like of being a little fairy, accusing the person you like of being a little elf, and repeatedly referring to the person you like as “an unearthly thing.”