MTL - Part-Time Taoist Priest - Chapter 53 Xianhe cited

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'.

SSR-ranked killer Mu Hui died in an explosion, only waking up to find herself transmigrated into the body of a vicious female supporting character in a book.

A back-to-basics(?) monster evolution novel.