The Demon Prince goes to the Academy 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.nl fastest updating comic site. The Summary is

I died while I was reading hate comments on my novel. I was already in shock over my death, but some 'Grim Reaper' appeared and told me that being a bad writer was a sin. To atone and make it into heaven, I was told I needed to survive past the ending in one of my novels. And so, I entered the novel ... "Damn it all!! Why did this have to happen to me?!" By all misfortune, the character I possesed was the Demon Prince, a character with no combat abilities—who dies at the very start of the story!!