Nidome no Yuusha - Chapter 100 - Worthless Four-Colored Grave 3

Death is sometimes not the end!
Dead prison!
This is a magical prison. It has the ability to draw the souls of the dead people of the world, and it also enables people to gain the ability of the souls of the dead.
When Qin Song woke up, he was shocked to find that he had come to the world of One Piece, and even more surprised that he found a prison in his body…..

- Description from Uukanshu

Description For a million worth of contract, she became a surrogate mother. He was the chief executive of the Empire and she was of lowly birth. With her adoptive father’s business falling into crisis, she agrees to his contract. She gave birth to twins: the older brother is healthy, while the younger brother didn’t breathe out. Fulfilling the contract with a huge monetary sum as the reward, she disappeared from his eyes. Six years later – he was still the cold high-profile president, but when she is accidentally imprisoned in the cage of his golden birds he pressured her harder and harder: “Woman, do not think you can escape my hands!” The old-fashioned man: “Mu Yazhe, you’d better leave her alone, this is the child’s mother!” The man becomes frightened, questioning the reason this child’s features bears such resemblance to… Associated Names 一胎二宝：亿万首席爱妻入骨

An ordinary (?) grandfather, Choi Chuntaek. In an effort to protect his granddaughter, he started the virtual reality game 'Arkstar.'

Then... he accidentally obtained a legendary class?