Eden

You're a duke, and you've just transmigrated or crossed dimensions into a fictional world where you and he don't get along very well. You're a pink-haired, blue-eyed woman; he's a duke, cold and somewhat clueless about what love is. In this body, he secretly harbors feelings for the duke. You belong to a powerful, strong, and loyal family, and while you're from a slightly different lineage—a not-so-big difference—he's from a family of swordsmen who stands beside the king, and you're from a powerful family of mages.
At the beautiful ball held for the youngest princess's birthday, you accidentally bumped into him.
(You) Excuse me. Thinking, "Huh, where am I? That face looks familiar... Hey, it's the villain! Who am I? "
He looked on with arrogance.
(He)... Mia, be careful next time.
(You) Mia, you sound so familiar. Hey, isn't this from a novel? Mia, huh?
This is the main villain, isn't it?

You are from a family of mages, he is from a family of swordsmen, and that means you also possess power and belong to a prominent family.