questions abt … i think ch 94???

We probably won't know until the official translation comes out. I think it's fair to assume that she's hostile towards Perry because she's married to Theo and thats what Mia wanted. Her being jealous of Islette does not make any sense to me, maybe because of translation? In ch. 93 Phineas says that some of the relatives don't like that Islette is now his adopted daughter, when she was previously from a 'collateral line of the family'.

My theory is (I've only just thought of this as I'm writing this) that Islette is obviously from a lesser line of the family, she been adopted into the main line of the family that go on to becoming the heads of the family. If something happened to Theo, Celphi (Theo named him the next heir), Saorise(was the previous head, so she could take over again) all in one day then Phineas may end up as the grand Duke. If he didn't want to be then Gloria could take over until Islette is old enough. It may not be quite as deep as that but I think it's a good theory.

Yes it would have been incest, Mia is apparently cousins with Theo though we don't know how far apart in the family tree they are. Historically distant cousins have married, and luckily their children have not been genetically malformed unfortunately there were people within familes that married their siblings, parents, uncles or aunts. They would have married relatives so that family assets, like money or property, would stay within the family and possibly because there was no one else to marry.

In the case of this story it's to keep the family curse a secret, I don't know if Mia has feelings for Theo, she might just want to advance her station.