What an unsatisfying chapter.
This one literally forced Lucoa to rape her sister with a curse and caused the collective downfall of an entire civilisation.
"She was willing to protect a human girl she has a personal attachment to" is not a sign of inherent goodness, trustworthiness, or safety.
...and like, where's the payoff for Lucoa? After all the buildup and death glares this chapter she's just awkwardly humming-and-hawing, resulting in "Well, I guess I'll keep an eye on her."
Half the chapter was jokes, for fuck's sake. Why even write in heavy relationship drama if you're not going to pay it off? All the other dragons get a full arc, Lucoa gets some offhand chapters with a bunch of downtime fluff in-between?
This was your shot to make Lucoa anything more than just the butt of a bunch of tit and shotacon jokes. To payoff all her buildup as an ancient goddess who doubts herself for an incident that wasn't even really her fault, and won't use her world-shaking power because of that self-doubt. And you did NOTHING with it. Her ancient foe... kinda just wants to be a high school girl and forgot all that ill will, and Lucoa is fine enough with it they just go to fuckin' karaoke and it's played off as another joke. What a letdown.