Manga really fell off, since the Sister appeared..
Really don't care about her past, but she's been a nuisance ever since she appeared, her entire Arc was really just a annoyance that dragged on for way too long with no conclusion whatsoever and it's still dragging on..
Like her whole character is just one giant contradiction with incest-bait sprinkled on top, the first thing she did, when seeing him again was literally trying to kill him, even without the kings order and now she's just going and throwing the whole family dynamic in a wack, also doubting we'll ever be seeing wholesome moments like in the beginning, since it's just impossible with that sister there