Funnily enough...if she manages to get a good hit in, it will solve the whole situation, coz that will probably release MC from her control, then he can tell them shes a succubus and they can put her down for good...BUT i dont think they will coz, by the looks of it, the succubus soul took over the duke daugther's body, like a regular isekai
so they cant straight up kill her, so they either make her submit and she becomes part of the harem, or they manage to exorcise her and the OG duke daughter will be part of the harem coz u know...she will probably have all the memories of that they did together.
Either way... this is a hard cop out, author could not decide which girl would get his 1st time, so they gave it to a random, now without that, they can fully make him fuck everyone without problem, Lily herself said it, it don't matter anymore ''who loves him more'' or ''who loved him first'', now is a full battle with all the Cards (sex) on the table.