I Have a Dragon in My Body 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.nl fastest updating comic site. The Summary is

Introducing a generation of Celestial Masters and returning to high school, he was surprised to find that he had a dragon in his body... When you are still very weak and face bullying, will you fight desperately or obey? In the previous life, he obeyed, but in this life... The romantic emperor rushed across the city, turning his hands over the clouds, and there was only one mind in mind: I am the king, and where is he? !!