I feel like this would be a realistic response if you read A LOT of obsessive and possessive manhwas before reincarnation. Half the time the psychopathic traits start showing during the childhood part of the story and just grows from there.
And the sister is supposed to be practically tortured and abused in the original right? My anxiety would be so sky high while trying to ensure she doesn’t end up like that. And what’s the easiest way to avoid it? Chaotically snatching the ML up every time they are about to meet so he never has the chance to get attached (￣∇￣")
She had a bit a of asgard reasoning but still plausible, the reason she threw a tantrum is because of Reincarnation confusion basically her old child personality came out
I'm sorry is the fl dumb? Why is she so freaked about the ml and former fl meeting? Both are young teen/child rn how tf their first meet is gonna be like when they were adult?