Valkyrie's Shadow - Chapter 3The Tiger and the Dragon: Act 8,

Suddenly becomes a mafia boss in a superpowers world and you are only 3 years old?! Ainsley Sloan, a 20-year-old avid anime lover, suddenly transmigrated into a body of a toddler. The father eloped with a woman, and the mother was just a surrogate mom. The two left behind their 3-years-old baby girl to rule over a mid-sized mafia family!No, this can't be! Ainsley was forced to embrace the abandoned Sloan Family and bring their family to the top of the dangerous mafia world– else she died. But, worry not! With the power of ultimate luck, the help of her loyal subordinates, and the protection of her cats-becoming-human, Ainsley will kick any enemies coming her way! A late encounter with a certain system even paved a flowery path for her. With its help, Ainsley will be the best mafia boss, and an extraordinary one! When other mafia bosses smoke cigarettes, Ain has choco Pocky stuck in her mouth. When other bosses swirl their glass of red wine, Ain blows her cup of hot milk! When other bosses blow their gun after a fight...Ain changes her diaper. Watch the baby take over the mafia world with her unique baby charm! 7 years later. A certain shrewd mini boss: "Ain, how about becoming my fiancee?" The boy five years older than the toddler waved a limited edition BL pillow case as a bribe. A certain system: kiddo, accept his proposal! sucks his money! Wtf you two. Fiancee your a*s!! I'm only 10!

I have a childhood friend.

What happens when a scientist from a futuristic world reincarnates in a World of Magic and Knights? An awesome MC is what happens! A scientist’s goal is to explore the secrets of the universe, and this is exactly what Leylin sets out to do when he is reincarnated. Dark, cold and calculating, he makes use of all his resources as he sets off on his adventures to meet his goal. Face? Who needs that… Hmmm… that guy seems too powerful for me to take on now… I better keep a low profile for now. You want me to help you? Sure… but what benefit can I get out of it? Nothing? Bye. Hmmm… that guy looks like he might cause me problems in the future. Should I let him off for now and let him grow into someone that can threaten me….. Nahhh. *kill*-

Alternative: Leylin is transported from an advanced technological era into a medieval world— except there’s magic. Equipped with “only” his quick wits and an A.I. chip fused to his soul, he sets out to become the most powerful magus the world has ever known. In a land divided into the Light and Dark Magi, the weak can either be cattle or disposable slaves. Only the strong can determine their lives, and only they have the luxury for virtue. Yet strength is only a tool for Leylin, like any other. His goal, in the end, is his own.

Male lead quick transmigration romance— originally called Soul Pawn Shop.

Hell’s ruler Xie Fei travelled through three thousand worlds to guide traders to redemption.

—Ding-dong! Welcome to the Soul Pawn Shop.

Note: 1V1 romance

- Description from Novelupdates