And with such a disgusted look too lol. Then the absolute awe once she saw Okiku. She claimed her woman and ruined the self esteem of two others at the same time. Commendable.
The main couple is super cute and so in love, spells and aphrodisiacs be damned. Also, our horny ghost is definitely hiding some hurt, but maybe she'll learn about love from our two love birds.
I think at least part of it is already clear. She liked that guy, kinda, they were flirting at least, but it never developed into a full-fledged relationship because she died.
Then she came back to life and was horny (valid, she’s dead anyways, can’t get pregnant or ostracised by society) so she went over the top on the mortal guy because she doesn’t get tired as a spirit. Dude died, and she realised after the “adrenaline” was out that “it didn’t feel good” because she can’t feel anything. She is a young woman, so ofc she felt regret that it was her first time and she couldn’t feel it at all — it’s supposed to be special, at least that’s what virgins fantasise about, but not everyone has a good first sexual experience. So it was traumatic to her.
I think her “evil side” will come from her being jealous. You can draw some parallels between Okiku/Ryouyo and Otsuyu/Ronin guy. It’s a ghost x living relationship, but the guy didn’t make it since the first thing she did was taking him to pound town. The relationship with her “beloved” didn’t get the chance to develop (I don’t see any indication he’s in the spirit world, dude was gone with no regrets), so Otsuyu seeing someone having what she so desperately craves (a connection that makes her feel something) might trigger something terrible inside of her.
Her face on that last panel made me think that, at least.