Tomodachi no Imouto ga Ore ni Dake Uzai - Volume 1, Extra

When Arran decides to become a mage, he quickly discovers that magic can be more dangerous than he had ever imagined. Soon, he finds himself hunted for powers he never knew he had.

Born with the fate of a slaughterer, but all he wanted to do was help.

I got hit by a truck and woke up in a world unfamiliar to me.[System rebooting… AI core active.][What can I help you with?]With a hologram screen floating before me, Chat GTP, the pinnacle of artificial intelligence.[Combat mode activated.][Here is the steps to create a atomic bomb.][Efficiency: 99.8%. Shall we proceed with conquest?]And with it, I became the most dangerous man in this world.

With his engagement at hand, the most terrifying and legendary person of the legal world, Fu Huai’an, returns with a son.

Before the engagement…

He asks, “Since you love Wen Moshen, why are you in my bed?”
She says, “Because I cannot watch idly as Wen Moshen’s woman enters an engagement with you.”

With a cigarette in Fu Huai’an’s mouth, he crosses his legs. Across the light cloud of smoke, he squints his eyes—watching as Lin Nuan’s slim arms wrap around his neck; he feels stirred.

So a person can love another so passionately.

“You call what you did a kiss?”
“…”
“What a pure lady!”

Fu Huai’an spews out a cloud of smoke and snuffs out the cigarette. With a mellow voice, he says, “Let me teach you what kissing is!”

But, what he teaches Lin Nuan doesn’t seem to be only a kiss…

- Description from Novelupdates