So I had this idea a few days ago and I wanted to share it
So right before the climax of the live action, there’s a big battle between the witches and the monster high students. Casta gets really hurt and Spelldon realizes and blasts whoever he’s fighting out of the way to get to her because that’s his big sister.
He tries to heal her but his magic isn’t strong enough alone. Valentine (Ellis) starts to come forward and they have a “do you trust me” moment and Spelldon has to put aside his (likely lifelong) bias against vampires to save casta. They use their magic together (with maybe draculaura too, as in “the three of us” song from the first one) and save the day!
But then they reveal that Ellis’ mother is actually the real villain. I think they’ll do a twist villain who is very similar to the protag like they did in the first one. Like, Komos was part human-part monster just like Clawdeen was, so since Draculaura is the protag now (or at least central character) the twist/“real” villain will be a vampire who practices witchcraft (and I don’t think it’ll be Ellis himself since they seem to get along)