The Main Characters That Only I Know - Chapter 3:

(Naruto + Single Heroine Tsunade + Romance + Action)A failed author transmigrates into the Naruto world, becoming the younger brother of Konoha’s White Fang, Sakumo Hatake, and the uncle of Kakashi. He gains a cheat ability—enhanced cellular activity.Coincidentally, just before the Second Shinobi War, he participates in a Jonin meeting where he supports Tsunade's proposal ahead of Dan Kato, marking his first encounter with her.From then on, he launches an intense pursuit, winning her heart during the war.Tsunade: “Kawakaze, why do I keep losing to you?”Kawakaze Hatake: “Because I’d like to live a few more years...”Kakashi: “My uncle is amazing, I’m his biggest fan!”Kawakaze Hatake: “Keep it low-key, keep it low-key.”

She is the underworld Ghost Doctor’s only disciple, who accidentally transmigrated into the body of the main wife’s daughter in the general’s mansion. She used to be a punching bag.Now, she stepped on her dregs of an older sister, put her father’s concubine in her place, and teaches any objectionable aristocratic ladies a lesson.

Her days are rather free and unfettered. But when did that cold as ice prince from the rumors, sporting a deadpan face all day long, fix his gaze on her?
He unexpectedly fawned and pandered to her like a devoted dog?

“Go away, you rotten man! Careful or I’ll needle you like a pin cushion!”

“Wife, why are you so fierce? As a husband, I’m so scared”
….the man is all smiles as he approached, his eyes gleaming with a cunning light.

- Description from Novelupdates

"Locke transmigrated into an era where everyone had Battle Beasts. Daemons were rampant and humans were forced to build walls around their dwellings while depending on Beastmasters to keep those monsters at bay.

Playing under the plum trees and riding on bamboo, those were the days of joyful play. It was when they first met.She was not shy but innocently charming, standing before the breeze with her hair flowing, her complexion as creamy as curds.After waking up, Xu Qingfan had returned to 20 years earlier, to the year 2002.That year, the sky was very blue, the clouds were very white, and the wind was very noisy.That year, his Childhood Sweetheart hadn't gone abroad, their parents hadn't gone grey, and he hadn't the worries of being unaccomplished.That year, he was six, she was five, and they both could fully experience the climate as snowflakes blossomed.PS: This book is also titled “Help, I'm Surrounded by Childhood Sweethearts” and “I Have a Little Too Many Childhood Sweethearts.”