The Poison Demon’s Strategy for the Martial Tower

[You have spread too much suffering across the Jianghu.] [From now on, make the world happy.] [You will be reincarnated in the Republic of Korea, 20XX.] Happy? “I only know revenge and pain!” And so it began. The story of how I — the Poison Demon — would create a (forcibly) happy world. — Description from novelcodex.org