Follow the Main Line and Become the Devil

The protagonist who was accidentally reincarnated into another world and followed the main line of this world is not a hero that everyone admires? As a demon king, should he be defeated by the brave and subdued by the goddess in the old-fashioned way? Or defeat the hero and kill the goddess? However, all the choices are yours, so go for it! Lord Demon King. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.