MTL - Heaven’s Shadow - Chapter 20 Dragon Lake Monster Fish

Reborn at the turn of the century, residing in Moscow, freshly off the plane, preparing to study abroad...Wang Ye only ever wanted a quiet life of modest wealth, to live his days in peaceful bliss.Yet, pushed along by the hand of fate, he found himself helplessly walking down the path towards becoming an oligarch!

I exist in the darkness, disappear under the bright light, and will eventually devour the sun and turn into the shadow of all things… Known by people as the indescribable terror of darkness; the king of shadows; the dark day; the existence of the shadow of the world , is still just a somewhat special high school student, facing a weird death game…

- Description from novelbuddy

Transmigrating into a world of cultivation, you find yourself at the lowest rung of the sect's hierarchy. Everyone wants to bully you to gain some benefits. Fortunately, there are always a few junior brothers and sisters who are 'generous and understanding', allowing you to improve peacefully and secretly grow stronger. Years later, unbeknownst to anyone, you successfully become a deity within the sect. This day, your master visits you at the sect's request.'The upper echelons of the sect believe you have been diligent and loyal over the years, and though your strength is mediocre, you are an honest person, so they've found a marriage alliance for you.''An alliance marriage?''Not exactly. The other family has a rule: marrying into their family means taking their surname.'Is this... becoming a son-in-law who marries into the wife's family?

Crossing to One Piece world, he became Roger’s younger brother.