Arifureta Shokugyou de Sekai Saikyou (WN) - Volume 1 Chapter 4

Bob is someone that hate people who praise Lord Buggy D. Clown as the strongest being on One Piece alongside God Usopp. His hate suddenly bring him to his death and even worse, his soul got transferred into Lord Buggy's body. How will Bob live as our Lord and Saviour Buggy?

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

Qin Chen was transmigrated to the Taiyi Holy Land where he became a servant in charge of sweeping the floor. However, on his 16th birthday, he was rewarded with a system where he was rewarded whenever he signed in at a new place.

When he signed in at the Empire Ruin, he was rewarded with the strongest Chaotic Holy Body and the Chaos Emperor Scripture.

When he signed in at the Demon Sealing Land, he was rewarded with the Probationary Royal Armies.

When he signed in at the Alchemy Palace, he was rewarded with the Divine-grade Alchemy.

When he signed in at the Herb Garden, he was rewarded with an Immortality Elixir.

When he signed in at the Empire Palace, he was rewarded with the Emperor-grade Divine Art, Revival.

…

Qin Chen thought he could just spend the rest of his life signing in at different places until he became invincible.

However, when the ruin of the Great Kingdom appeared inside the holy land, people from other holy lands, prestigious families, and even ancient empires gathered to defeat the All-Powerful Demon King who appeared with the ruin. The Demon King had killed countless people and had planned to destroy the Taiyi Holy Land.

Qin Chen was left with no choice but to step up. When he killed the Demon King with a single slap, he sighed, “Why do you guys have to force a mere servant to act?”

A dark soul, damaged by his past An angel forced to be his mistress. Can anything go right? Would they ever be able to fall in love? Will she be able to see past his darkness? Will he be able to protect her when danger comes knocking? Find out in this book... An Excerpt*

''You know what you are getting into, right?'' He asked, crossing his legs, he raised a brow;

Tiana's lips slanted and her eyes narrowed at him;

''As long as you pay me, I'll do whatever you want. '' Nicklaus was amazed by her sudden audaciousness;

but he was sure she was just trying to seem bold, He knew her, she was just a weak, trembling soul, and she was trying so hard to mask it;

A smirk appeared on his lips as a thought came into his mind; ''Whatever I want? ''

He asked again and Tiana replied immediately without a second thought;

''Yes, Mr. Nicklaus, whatever you want. ''

''Alright then, I want you to strip yourself and go lie down on the bed. ''

He did not have any thought of touching her; he just wanted to see her reaction. But what Tiana did next shocked him.