Okay so I have an idea on how to explain how Y/n can kill Angels.
Exterminations are only supported to be targeting Sinners. Hellborns like Charlie and the Goetia's aren't targets, only the sinners.
I could explain that Muzan was once a powerful Hellborn demon, maybe even having him be the Son of one of the sins explaining his strength.
So when Muzan puts blood into a demon (Or a Yokai), he's essentially turning them into a Hellborn demon.
If you want the biological explanation for it, I've got nothing excet welcome to the world of Hell and Anime, you're going to hate it here.
And because that blood is of a power demon, specifically the Son of one of the seven deadly sins, Y/n would be able to do it since he's a Kizuki.
Someone with a lot of Muzan's blood in him.
Also, I know I've been very absent with this story but I have been very busy dealing with other books, so bare with me.
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The Uppermoon Overlord (KNY demon reader x Hazbin hotel/Helluva harem)
FanfictionRemake of an old book I made. Y/n had been another mindless pawn of Muzan Kibitsuji until the day of his deth. From low level Yokai of Japan now an Overlord of Hell, Y/n will now live his life in one of the strangest places in all of hell. The Happy...
