Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 16 - 16-50. Vampires

Miguel transmigrated into the Wild Beast World in the body of a useless teen with the same name as himself after he was betrayed by his disciple, the Harem Emperor, for a knowledge and universal secret that he recently uncovered.In the Wild Beast World, humans could contract Wild Beasts through their Summoning Grimoire, a mysterious book that fated individuals can awaken at the age of 18.In this world of summons and beasts, Miguel awakened with the Beauty Sign-In System, which allowed him to contract legendary beauties as long as he signed in at a specific location.On his first sign-in, he received the Holy Daughter of the Red Family, the Fiery Empress of Legend.Using the Wild Beast World and the Sign-in System as a starting point, Miguel swore to return to the Immortal Cultivation World and settle scores with the Harem Emperor once and for all.Follow Miguel's journey as he reaches for the apex, becoming a legendary figure in all worlds.

The course of commitments never did run smooth.

Zhao Du'an, a government official leading a cautious life, finds himself transported to another world where he becomes the favored 'pretty face' of a female emperor and an oppressive, power-abusing villain. Before he can relish the moment, he faces mortal danger for releasing a national criminal. Cornered and desperate, he plans to soothe the female emperor to seek mercy, only to discover his 'leading gigolo' role is a sham.Worse still, his notorious reputation prompts officials and heroes alike to impeach and eliminate him; and martial artists and clerical magicians consider him a disgrace. Overwhelmed, Zhao Du'an decides it's better to stop being human to survive.Starting by betraying his allies, he becomes the Emperor's top lackey. Years later, amidst heavy snowfall in the capital, the female emperor Xu Zhen Guan sighs atop the city tower, 'It was supposed to be a pretend companionship, how did it turn real...'Also known as 'Deceiving and Flattering at the Court of Great Yu', 'The Record of a Villain Going White'.