In Kerren's story before, Mythicals weren't out in the open, they were hidden. Why?
Well, before the renaissance, when what we would come to know as the Black Plague, a Reapers apprentice, the last recorded human medium had been misled to think that taking over would help protect everyone more. He took over and ended up killing a good lot of the population, both Mythicals, and Humans.
In this iteration, Mythicals, under orders of the High Council had them perform a mass memory spell to wipe the human's memories, as the apprentice had killed more humans than Mythicals and they were wary of retaliation. As such, the Mythicals stuck to the shadows.
However, in this retelling, the humans acted first. They put themselves on the Lower Council (they can't get into the Higher Council). They started controlling a lot of things, this has lead to a lot of dislike on both sides. Though some have found ways to live together (for instance Mrs. Calloway being a witch in a wealthy apartment, or Mr. Reddings, the head of Kerren's old school is a halfa Cyclops). There is still disilike, and Humans still regulate a lot of Mythicals things very heavily, such as potion ingredients or spell books.
The only Mythicals that can't be regulated by anyone, are the Reapers, and the Gaias. They only answer to the High Coucil.
The only thing that Humans and Mythicals seem to agree on is that Halfas (A half mythical/human) are... Well. Looked down on, for the most part. But even halfas with two Mythical parents are looked down on.
It's going to be Kerren's job to put everyone on an equal plane, and start to heal those wounds caused so long ago.
If this was rambly, I apologize. That's how I tend to world build. I word vomit.