To understand what is happening we must go back in time to when the nethereal sisters parted ways with Daimon at the entrance of the castle, seeing the masked silver haired youth disappear into the black portal, the crazy girl smiled at her sisters before saying.
"Come on, let's have some nice sisterly bonding time~".
And with those words, Reyne and Jasmine were dragged towards the caste by Sarah, naturally the gates were closed so that they couldn't enter, but that's why Daimon left behind his black sea emblem with those three.
Well, he left it in Sarah's care, because he knew the crazy girl was going to be the one at the vanguard for sure, and he was right, Sarah walked a couple of steps ahead of her sisters with a seemingly careless expression on her pretty face, but with bloodthirsty eyes.
"Please do the honors", casually said the crazy girl as she threw Daimon's black sea emblem at the door, making the rune shark manifest itself in a rush.