DxD: Scion of Lucifuge - Chapter 165: Sightseeing in Kyoto—Clash Against Khaos Brigade!

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Adrian Hudel has always been the invisible son in the Hu family, overshadowed by his elder brother Wryn, who was groomed to inherit the family business. Adrian’s only solace lies in his passion for painting, a dream he clings to amidst the cold indifference of his father, Wuner Hudel. But when Wryn abandons the family overnight, fleeing from an arranged marriage to the richest man in the country, Ethan Levistis, Adrian’s life takes a devastating turn.---The cover is mine.The cover is of MC-Adrian Hudel.Free to collect.BL Story.

Various monsters came out from mysterious gates that appeared all over the world. Along with this incident, humans also gained power and were called hunters.

Radmilo Laiv is a hunter with the power to control time. He spent his life serving the world government and becoming a hero. However, he was killed because his power was considered a threat to the government.

It was a stroke of luck that Radmilo could return to the past because of his powers. In this life, he doesn’t want to be a hero anymore. Should he play the evil role and become a villain?