Stranger's Handbook - Chapter 59: The Wedding Ceremony

Known as the country’s top onmyoji, Yuuma Kisaragi, who lived to the age of 99, awoke to find himself in an unfamiliar forest. A voice echoed in his mind, revealing that he had been reincarnated into another world at the age of 20.“Good morning, Master. Skip the greetings and please defeat the goblin in front of you.”The voice belonged to a skill acquired during reincarnation called “AI,” designed to assist Yuuma in his new life. When the skill, AI, took over the form of a golden-haired fox yokai, the familiar shape of Yuuma’s shikigami, he decided to embark on a new life alongside AI-chan.The onmyoji and AI-chan’s second life began, tackling various challenges and formidable enemies with the strongest spells and shikigami.

Beasts of all kinds—spiritual beasts, demonic beasts, rare beasts, celestial beasts, ancient relics, dragons of fortune, sword spirits, corpse puppets, gu insects, mechanical marvels, and elemental spirits—every form and technique can be mastered.The story begins in a third-rate cultivation sect, the Beast Taming Sect……Struggle through the weak paths; ascend with the mastery of beasts!

The Special Investigations Unit is a covert organisation that no-one in the city knows about, dedicated to investigating bizarre occurrences beyond the comprehension of the living. The Chief Zhao Yunlan isn’t a simple guy either, being the inheritor of the Guardian Order, he has always been a righteous conformist, excelling between realms of the living and the dead. While investigating a school suicide case, Zhao is attracted to the calm and reserved Professor Shen Wei, but the Professor seems to be rather fickle towards him…

- Description from Novelupdates

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.