I'm the Demon King, so Please Just Turn Around and Leave

For a few days, the 'border' had been in an uproar, and now the interior of the castle was noisy. “…How annoying.” The sound of flesh being sliced and the clashing of metal echoing from outside the building, along with the sound of footsteps rushing toward the room, disturbed my sleep, and— K-boom!! With a loud crash, the door shattered, and uninvited guests stormed into the room. “Are you the Demon King?” “…….” I sent all the heroes, who had come to visit for such tedious reasons, to the ocean all at once. Then, a few days later, strange articles began to appear in the human realm. [Breaking News: Heroes who went to slay the Demon King return with jewels…] [Fact: One of the heroes...