Debuff Master

Debuff Master is a Manga/Manhwa/Manhua in (English/Raw) language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.com fastest updating comic site. The Summary is

Han Taesung, a livelihood-type gamer cornered at the edge of a cliff. “I have been watching you for a long time.” Deus, a hidden NPC of level 999, appears In front of Taesung! [Would you like to become the disciple of the hidden NPC Deus?] [Yes!] Thus the master’s teachings began!! “Two blows are not cool, you must defeat enemies in one blow.” Taesung becomes a who knocks down enemies in single blow. Everyone will fall prey! Defeat them in one hit!