Ichiban Ushiro no Daimaou - Volume 8, Chapter 4 — The Very Last Demon King

In the third year of the reign of Yu State, it rained in the city of Weizhou.

Li Ang woke up in a daze, dreaming that there was a sword hidden in his head.

- Description from novelbuddy

The King of Hell sentences you to death by midnight, but I can ensure that you live past morning.

The young man, Qin Lang, received the inheritance of a poison school by chance. He uses poison to kill people, uses poison to save people and he uses poison to chase beauties. With body of ancient extinct poison and a body of a martial artist, he walks around the city, and wanders around in the underworld.

- Description from Novelupdates

Rudel Arses, the first born of one of the ‘Three Lords’ of the Courtois Kingdom, is from a corrupted family, but at 5 years old, he saw a dragon in the sky and his dark future as a villain changed. He was considered an idiot, but was that true? How would his effort to become a dragoon change the kingdom?