I am the Lord of the Underworld is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Mutation strikes, the world is overturned, and after a hundred years, humanity enters the era of universal job change. Chai Yu starts with an awakening of an SSS-level talent – the Apostle of the Underworld. Infinite undead, skills multiplied by a hundred, mental control – watch as Chai Yu sits on the high platform of ten thousand bones, deciding life and death with a wave of his finger. Three years later, the Void Clan invades the Blue Star. Chai Yu opens his eyes and says, “Hmph, mere aliens, easily exterminated with a flick of my hand!” In an instant, the Kingdom of Death descends, and billions of natural disasters engulf the void.