Touch My Little Brother and You're Dead

One day, I woke up as Rosalite, the older sister of Asterion in the novel, “Asterion of the Twilight.” I may not be the main character, but it’s not so bad. Rosalite’s little brother, though, is fated to die in the story at 20 and that just seems really unfair after all the drama he’s been through (did I mention his story is a BL?). Now that I’m Rosalite, I decide to save him. But no matter how hard I try, he just keeps dying and every time he dies, I turn back into 16-year-old Rosalite. Ten or