Another Stupid Isekai - Chapter 58

A former sporting rifle shooter genius transforms into the ‘Juvenile Butcher’. While originally supposed to have received the death penalty, he was instead fortunate enough to have entered a secret and highly regarded armed force, throwing himself into the ‘Nirvana Project’.

The scum’s or villain’s long road of transformation was tentatively set to the world:
The abandonment of the educated youth’s wife (Completed)
The hidden marriage of the scum film emperor (Completed)
The best brother in the world (Completed)
The Phoenix male who destroy the bridge after crossing the river (Completed)
The treasonous general (Completed)
I’m an honest man (Completed)
To become the top scorer in the School of Agriculture (Completed)
The soft rice man’s self-cultivation (Completed)
The whole world is reborn (Completed)
I want to survive on a desert island (Completed)
The stallion male who has seized the opportunity (Completed)
The perverted self-salvation (Completed)
The spring of the loafer (Completed)
The misplaced life (Completed)
The miser career (Completed)
The ghost is out of feeling (Completed)
The Queen’s favorite husband (Completed)
The vicious girl with her godfather (Completed)
I want to be a good person (Completed)
I does not tear up the family (Completed)
The perverted common plant (Completed)
The Mary Sue’s men (Completed)
Every time I was reborn, someone wants to kill me (Completed)
The old people’s counterattack path (Completed)
The global evolution (Completed)
When I became a net red (Completed)
For you, good person (Completed)
His heart had white moonlight (Completed)

- Description from Novelupdates

A man who gets into the Webtoon comic he reads and becomes the most feared S rank Villain, but actually he is a loser??

Akira Kitagawa, a quiet and unremarkable second-year high school student, has come to accept his lonely, mundane life after losing his parents in a tragic accident. No friends, no excitement—just peaceful monotony.Until one day… a girl literally falls from the sky.Sera Rymer, a fiery and seductive mage from a world of magic, crashes into his life—naked, powerful, and completely confused. Bound by an ancient pact of Master and Slave, she must now live under Akira's roof, turning his boring world into a whirlwind of magical chaos, awkward steam-filled encounters, and otherworldly drama.From laundry mishaps involving spells to battling demonic pursuers from Sera's realm, Akira's once dull life is now anything but ordinary. But as their bond deepens, secrets unravel—and the “God” behind it all might have very different plans.Can a lonely boy and a wild mage girl find meaning—and maybe even love—in the absurdity of it all?Tagline:When magic crashes into your mundane life, expect steam, spells, and soul-binding surprises.Tags:Romantic Comedy, Fantasy, High School, Ecchi, Magic, Isekai Girl, Master-Servant Pact, Slice of Chaos, Slow Burn Romance, Fanservice, Opposites Attract, Everyday Magic, Harem (Optional), Steamy Situations, Lighthearted Drama, Tsundere Heroine