When Capella she stepped on Crusch, which prompted Subaru to tell Capella to get her leg off of her, to which Capella responded whether he’s infatuated with her beautiful legs or just Crusch, who she called female meat, saying she does have quite an erotic figure as she stepped on Crusch’s breasts. Subaru responded by saying Capella is not worthy of holding her Crusch under a foot and launches a piece of the building at Capella with his whip, which she easily started regenerating her wounds from. In the meantime, she sprouted a long tail and knocked Subaru to the side with it before asking if her beauty rendered him speechless. That was the second time Capella has tried to fish for a compliment, so this may point to an insecurity she may have.
She later hinted to Subaru what the passed out dragon and flies really were since he didn’t get it, and when he finally realized the reality of the situation, he questioned why she did that. She prodded him by asking if he found it disgusting, to which Subaru called it blood-curdling. Capella coolly says that it’s so disgusting and repulsive that it makes him hate her. She says seeing what he saw regarding the flies and the dragon made him hate her on a visceral level, and that’s the “right” answer. She said that no one could love creatures like those. Subaru then requests for her to kill him, to which she says she’d never do something so barbaric and throws out that she wants as many people as possible, for as long as possible, as deeply as possible to love her as being the reason she doesn’t kill him ’cause it’s her wish, which is quite odd given she’s been pushing him to hate her, so I take it that she does have an insecurity after all, probably about her own worth/beauty.
My takeaway from these incidents is that Capella very much wants to be loved and that she pushes others to hate her ’cause she fundamentally believes that no one can love her. Capella transformed other human beings into creatures she feels no one can possibly love ’cause that makes them more grotesque than she is, which is reinforced by her saying she wants as many people as possible, for as long as possible, as deeply as possible to love her, so not killing Subaru would mean the possibility is there for Subaru to love her physical form more than the flies as long as she drags the situation out.
Subaru then makes a move to save Crusch, and Capella said that Subaru always ends up drooling over that female meat ’cause he wants her so bad. Subaru notes that there’s already someone he likes, and Capella remarks that can he really swear he hasn’t had lewd thoughts about Crusch for even a second? She asked him if he didn’t think about stroking Crusch’s hair or kissing her supple lips. Capella then raged about how Subaru shouldn’t dare take his carnal desire for the one he fancies he can’t speak of in the open and call it love. She then proceeds to transform into Emilia although without the right outfit and without the hair clip, which shows one of Capella’s powers may be to able to read your psyche and be able to transform into an approximation of your ideal lover without knowing all the exact details. She then belittles Subaru by saying if Emilia were a fly, he wouldn’t still love her ’cause she believes love is not possible without physical attraction.
Wilhelm noted in Episode 54 that the Emerada Lugunica who existed over 50 years ago was beautiful and also ruthless, which matches the description of Capella, so Emerada Lugunica may have somehow been transformed if she had an identity before Capella currently with the dragon blood. But does Capella herself even think much of her beauty herself? Judging from that previous content of Capella, she doesn’t believe that having high sexual desire for someone is the same as having love for that person. When you couple that with her fishing for compliments, I believe Capella may have slept around a lot with tons of men, but none of them loved her or accepted her for who she is, which might be why she calls others meat scraps ’cause she personally feels that she herself is a piece of meat like in the manner she spoke degradingly about Crusch. Capella would call others meat scraps ’cause if everyone else is a meat scrap, then that elevates herself by bringing down everyone to her level. Thus, she still fishes for compliments and does all she does ’cause she still clings to the hope that somebody will love her even if nobody has in all her years of living.