Gonna wager a guess and say new antagonist is a sister or cousin wanting to take "the throne".
I mean, that posture, that stare, how she treats subordinates. All of it makes me think, "spoiled child wants what big sister has".
Chekhov's face masks. Subtly done and yet disappointingly unsurprising.
Anyway, we're in chapter 14 - I doubt it'll suddenly turn super serious and plot heavy. I suppose it might mean they can't go further than kissing because her virginity protects her or somesuch thing.
I think she had lover in past or at least someone who close to her and died.
Then she either lost her memories or forced to forget after living that long.
There's also the butterfly (Yoku-ben) mentioned in the dictionary over the word "Desire" (Yoku-bou). pag. 31.
However, when doing some quick research I couldn't find any info on a butterfly shaped like a flower. Instead, the engine threw the name of a blue/purplish flower shaped like a butterfly with a bird-like tail. The scientific name for the flower(not really the plant) is Clerodendrum Ugandense.
I don't know if there was some stuff lost on TL there or some other thing going on with the plot, but this flower kinda matches the description too much.
Casually this flower is full of nectar, so it atracts a lot of insects like bees and well... butterflies.
Why did I do all this on the first place? It was fun.