Behind the battle of The Hero and The Demon King is a Manga/Manhwa/Manhua in (English/Raw) language, REINCARNATION
series, english chapters have been translated and you can read them here. You are reading Behind the battle of The Hero and The Demon King chapters on VipToon, fastest updating comic site. The Summary is
Verna reincarnated into a modern Japanese RPG game world as the son of an aristocrat— that is, reincarnated not as a main character but someone whose name is not even mentioned. On top of that, as his skill is boring and dull, he wasn’t a person who was fit to be part of the hero’s storyline. The only thread of hope is his friendship built between him and Hero Mazell, and his knowledge and wisdom passed down from his previous life… The start of a full-scale fantasy battle manga told by a mob and a legendary hero.