Iris doesn't know that the Grand Duke is her real biological father. The only people who knows about this is Iris's brother, her uncle/aunt, her cousin and the Grand Duke himself, although he isn't sure about it, he has a hunch she is.
Oh! I forgot one person! Sophie knows too, but after losing her memory, I'm not sure if she will remember.
wait if the duke himself knew why did he still took in that bitch nera? i mean i dropped this when that arc is about to start but i saw that she calls him father and whatnot
Maybe because the Duchess wanted Nera as her daughter? Remember, the one who took Nera in wasn't the Grand Duke, but the Grand Duchess.
oh I see, I didn't know cause I dropped it when I knew that he's gonna take her in. thanks btw!
Why the hell are they trying to hide the fact that the duke is her father?