Thanks for Asking. I Just Became Doma and Backstabbed Muzan in Demon Slayer

Doma: Sir, there’s a fist pillar facing me.

Sanemi: Sir, there’s an ice pillar facing me.

Muzan: You two are both pillars.

He transmigrates into Demon Slayer and becomes Doma, Upper Rank Two. From the start, Muzan force-feeds him his blood.

Just as he thinks he’ll have to spend his whole life surrounded by filth, the [Interdimensional National Destiny: Radiance System] activates! Do good deeds to earn [Radiance Points], purify demon blood, exchange them for future technology, and grow stronger without limit!

From then on, the Demon Slayer world welcomes the strangest “demon of holy light” ever.

[You refuse to eat humans and comfort a frightened girl. Radiance Points +100! The demon blood in your body is purified, and the agony turns into a warm current!]

[You secretly save a village from slaughter. Radiance Points +10,000! Exchange permissions unlocked. You obtain “Controlled Nuclear Fusion Technology” and forge your first “Crimson Blade: Solar Furnace”!]

[You show Akaza the “Way of Radiance” and talk him into submission! Upper Rank Three becomes a “Penitent Holy Knight” and fights for you!]

[You establish the “Radiance Faith” and teach the Demon Slayer Corps the “Holy Light Breathing Style”! From then on, the tragic organization becomes the “Holy Light Knights,” every member a dragon, their radiance illuminating the world!]

[You send a “negative-radiance biological sample (demon cells)” back to the modern era! You drive global evolution forward and earn the title “Pioneer of Civilization” from an academician of Longguo!]