Vainqueur the dragon 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

Vainqueur Knightsbane is your average dragon: a fire-breathing lizard who loves to sleep on his golden hoard, kidnap princesses for fun, and make the life of adventurers miserable. Vainqueur's only pleasure in life is to watch his treasure get bigger, one coin at a time. So when a would-be thief turned unwilling minion tells him about "classes," "levels," and "quests," Vainqueur wonders if he should consider a career change. Can the world survive the first dragon with levels?