A Hero trained by the most evil demon king is unrivaled in the academy of returnees from another world

Kyouya Kujou put forth his best efforts to save the world, but due to his lack of special abilities granted to heroes by goddesses, he failed. This caused him to be ridiculed as a “Failure Hero” at the academy, and he was deemed unworthy among the returning heroes who successfully saved multiple worlds. However, what they were unaware of was that Kyouya had been trained by Felice, a notorious demon king who had demolished countless worlds, for 30,000 years.
Thanks to his training under Felice’s wing, Kyouya had unlocked latent abilities that surpassed even the most powerful of heroes. He now possesses unmatched power, and his epic story is about to be revealed – a story of a hero that was trained by the most formidable demon king the world has ever seen.