Code Demon is a Manga/Manhwa/Manhua in english language, Manhwa 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

Forced to take over his family’s technology company, struggling college student Kaito agrees to the terms of a seemingly harmless video game meant to be an online tutorial for IT, only to realize too late that he’s become a contestant in a battle royale where he’ll fight to win a passing grade…or die trying.