Jaryuu Tensei: Isekai Ittemo Ore wa Ore

There was a nameless man who worked as a corporate slave, one day he died miserably in an accident. But when he woke up he became an evil dragon in a different world. The man thinks. “Hmm, then this means I don’t need to work, do I?” He became the strongest creature at the level that even demon king and hero couldn’t compete with him at all, so that man decided to live as leisurely as he liked. (Source: Novel Updates)