Wait, You're Still This Weak With a Hero's Blessing?

This is a world of swords and magic, and a story of heroes versus the Demon King. Leo, the previous hero, lost the hero’s blessing after successfully defeating the Demon King. But he still wanted to put an end to the century-long war between demons and humans. Unfortunately, a new hero appeared, and his bloodlust toward demons was twisted beyond all reason. To make matters worse, a mysterious cult appeared out of nowhere and kept causing trouble for both humans and demons... What should Leo do now? Is there really no choice but to use that move? (I’m not good at writing blurbs, so please read the story itself.)