Divine Beast Ascension - Chapter 6

Lin Wudao has traversed, and there is an invincible corpse collection system.

As long as you collect the corpses for the strong, you can get the things they owned or touched as rewards during their lifetime, and the obtained items are still strengthened.

Lowest, ten times stronger!

[You collected the corpse of the great emperor Jiang Taichu, and gained ten thousand years of cultivation! 】

[You collected the body of your fiancée Jiang Qingxue, obtained the Zichen Sword, a humane spirit weapon, and after strengthening it ten times, it was upgraded to become an extreme spirit weapon, the Xuantian Ancient Sword! 】

[You collected the bones of an immortal, obtained a ray of immortal origin, enhanced it by 100,000 times, and upgraded it to become the original origin of Hongmeng. After refining it, you can be promoted to the immortal emperor! 】

…

Since obtaining the invincible corpse collection system, Lin Wudao has embarked on an invincible road that can push through the ages and suppress the heavens.

- Description from novelbuddy

In regards to the MMORPG Cross Reverie, Sakamoto Takuma boasted an overwhelming strength that was enough for him to be called the Demon King by the other players. One day, he gets summoned to another world with his appearance in the game. There, there are two people that insist “I am the real summon master.” Takuma gets slave-turning magic used for summoned beasts cast on him by the girls –

In the ruins after the war, the empire is reborn from the ashes.For supreme glory, it competes for supremacy in the world and aims to dominate the globe.

Chen Rui, an otaku from earth, is reborn into a human body in another world, who falls into the legendary evil, brutal world of the devil called Mozu where humans are treated as food. He has to survive while facing horrors of the devil, violent dragons and a variety of power enemies depending on a strange super system chip and his wits. Surrounded by Devil’s beauties such as black-bellied lolita princess, cold queens, violent dragons, charming poisonous devils …

Wanting to live in the Devil’s world is hard! Wanting to live in the Devil’s world as a human is harder! Wanting a human to be the devil’s son-in-law is hardest!

Let us see how a small otaku uses power and strategy step by step starting from an ordinary human to writing a legend as the devil’s greatest son-in-law.

- Description from Novelupdates