City: I'm Back from the Other Side of the Starry Sky

The Star Demon Emperor returned to the city and found that only two years had passed on Earth. Return with an invincible attitude, roaming the city. Company president? Sorry, that's just my slave. A martial arts master? I can trample hundreds of them to death with just one kick. A person with superpowers? ​I'm not saying that, everyone here is actually rubbish!