NIGHTS OF HALLOW - Chapter 27: Perdita - The Benefactor.

When necromancers perform a great ritual to summon an undead servant, they bring a powerful vampire into their world. And now, their fate is sealed as food, but for Klaus, this is just the beginning of his adventure. In a cruel world where people will do anything for power and immortality, he is already very strong and immortal, so what's left if not start a family and have fun stepping on arrogant people through the way?

[Class changing to the hidden class, Demonic Swordsman.] [You are the first one to discover the hidden dungeon.] [You are the first one to discover the hidden…] [You are the first one…] [You are…] I’m a gamer who uses ESP.

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.

I’ve had enough of being transmigrated into books.