I really enjoy fix it SI and redo novels where the MC helps saves characters from their tragic fates. Whether it's fan fiction or something like MC reincarnating as the villainess' parent, sibling, or love interest. OR second chance redo first. I'm specifically asking for fix-it focused on saving one person. Doesn't mean he can't save others, just make it so the main one he's saving is the other lead. Saving can mean save them from their circumstances like a Harry adoption fic or saving a character from death like a RWBY redo Jaune fic or saving as in giving them redemption like Azula. I'm fine with originals, translated, or fan fiction. PS: Never seen Elfen Lied, but is there a fix-it hurt comfort fic cause that sh*t needs an OP fix-it.
the MC's missions is to bring happiness to specific people / change their destinies The Analects of Righteous Father’s Collapse
From Fake Dreams, it's a Fate/stay night fanfic. It's hardcore fix it but stupidly long and sometimes overcomplicated. Still it's pretty good.