@DarkEboreus
@Reyven
Prince didn't know there was any difference between sisters .
Her father was all too happy to do whatever to please his younger daughter.
The magician was engrossed in research at that time.
So basically, they either didn't care enough or if they did care, they didn't react quick enough before she tried to sacrifice herself.
But as proven in previous chapters.
Little sister is obnoxiously selfish (as if that wasn't obvious) causing friction between the prince and other nobles by insulting them often. So he regretted it a bit.
Genius magician now resigned to focus more on studies.
Duke... was all too happy when she decided to sacrifice herself and phrased it to bring glory to their house.