Yuusha no Segare - Volume 1, Chapter 1 − Hideo’s Saga Part 2

One of the seven strongest people on the continent, the King of Mercenaries. He started a war to avenge his fallen family and destroyed territory but failed and lost his life. However… “Wow, I’m alive?” I returned to the past, back through time. A perfect opportunity to right my regrets and reverse everything. It doesn’t matter if people around me point fingers, calling me a scoundrel, or dismiss me as tr*sh. Because… “I’ve got a plan.” “What plan?” “A plan to destroy everything.” There won’t be a second failure. This time, I’ll wipe out all my enemies. …But first, I need to rebuild this damn estate.

One moment I was a grown man—an engineer with a decent job and way too many spreadsheets. The next? I woke up in a kid’s bed, staring at glow-in-the-dark stars on the ceiling… in Malibu.Turns out, I’m Jake Harper now. Yeah, that Jake Harper.“Wait… I had a bitchy mom and a simp dad?”Yeah, the behaviors don’t make sense — just roll with itYeah, the years don’t match — just roll with itpatreon.com/MHJunior(I am not the owner of any show, credits to their respective creators)

Once through the pirates, Lu En became the son of Monkey d Dragon, a grandfather named Monkey d Karp, and an unreliable and neurotic younger brother named Luffy.

Fortunately, the ghost back system is activated!

The completion of the ghost back is 10%, and the training effect is increased by 100 times!

The completion of the ghost back is 20%, and the training effect is increased by 1000 times!

…

One day, Lu En, a ghost-backed master, appeared in front of Luffy who was shouting to go to sea, and made Luffy cry on the spot.

Luffy: “The pirates in the sea are all monsters like my brother? I don’t want to go out to sea!”

Garp: “For a long time, the two boys, Long and Luffy, with small arms and calves, I really doubt that they are not my sons and grandsons. Like Lu En, they are the grandsons of the old man!”

Warring States: “The strongest creature in the sea, land and air is Kaido? No, it’s Lu En!”

- Description from novelbuddy

This is a story that follows the courtship between a stone from Hell and a god from Heaven that begins in the underworld and spans for three lifetimes in the mortal realm.