Amazing Doctor With Super Vision - Chapter 624 - The Third Genetic Mutation

Meet Sora and Shiro, a brother and sister who are loser shut-ins by normal standards. But these siblings don’t play by the rules of the “crappy game” that is average society. In the world of gaming, this genius pair reigns supreme, their invincible avatar so famous that it’s the stuff of urban legend. So when a young boy calling himself God summons the siblings to a fantastic alternate world where war is forbidden and all conflicts–even those involving national borders–are decided by the outcome of games, Sora and Shiro have pretty much hit the jackpot. But they soon learn that in this world, humanity, cornered and outnumbered by other species, survives within the confines of one city. Will Sora and Shiro, two failures at life, turn out to be the saviors of mankind? Let the games begin…

The doomsday fell upon the earth when a dragon coffin sealed under a snow mountain for ages shifted, and the civilization of gods and devils began. The whole universe turned into a fantastic new world where everyone could rise to the top through cultivation. A lucky young boy seized the opportunity, and started his journey to be an overlord in cultivation.

- Description from Novelupdates

Once upon a time, the Devil fell in love with one of the King’s many wives. One night he went to her room disguised as her husband and made love to her. She got pregnant with his child. Knowing this The King ordered her execution believing his wife cheated on him, but then the Devil appeared to the king making him a deal. In exchange for great power for his Kingdom, the King will let his wife Sire The Devil’s Child. The King who was greedy for power agrees to the deal and his Kingdom becomes one of the most powerful Kingdoms and the Devil’s Child, the seventh Prince of the Kingdom.

The young lord of a small and weak country saves a dragon beside the sea one day.