It's Your Turn To Cry and Beg, Dear Uncle - Chapter 5: The Confrontation

Nik Faran, a son of the miserable harlot that lead a life of a miserable gigolo. His birth father is one of the top swordsmen that gave his mother the glory of entering his chamber now remained unknown.Passing years allowed Nik to polish his skills as a prostitute before he was suddenly made aware of the rumour that was the mythical Incubus Society.

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…

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

I’ve reincarnated as the reverse harem game’s villainess, the one and only step-daughter of the Eckart duke family.