The Strongest Assassin Reincarnates in Another World - Chapter 439 - War

Two heroes of the game Legend of Heroes 2 who were rotten waters*.

After a tear in reality pulls Kagari Shuya into a white room he discovers a futuristic interface for reincarnating in a different world. After looking through the different races and skills he unlocks a new race, Lucivault, a type of vampire with none of its characteristic weaknesses. All set to start his life in a new world, Shuya is confused to discover that he is enveloped in darkness. As it turns out something went wrong when he was transported and instead of appearing where he was supposed to, he appeared in an underground cave. Shuya faces untold dangers, runs for his life, before finding his way out of the underground world. After escaping he meets his Shishou and begins to learn to fight with a spear. There is also a cute black cat named Rollo.

Xiao Yi, an orphan raised by a disrespectful old man, possessed mysterious ancient martial arts and a unique skill in traditional Chinese medicine. At the age of twenty, he suddenly received the most baffling mission from the old man: to attend the renowned first-tier university, University Z, as a student, initiating his spectacular modern urban life. In the city, he began to write his own eternal legend...

Police officer, would you believe me if I say this is an Iyashikei game?