WARNING: The following contains spoilers for Episode 12 of The Misfit of Demon King Academy, now streaming on Crunchyroll.
Ever since he first arrived at the Demon King Academy, Anos Voldigoad has been hearing the name "Avos Dilhevia," a name that everyone else falsely associates with the true Demon King. The name just became a reality. Anos is in the middle of inter-school practice battles, but now, Avos Dilhevia is steps into the light, taking Anos and Diego by total surprise. And he's got a plan for the human and demon realms alike.
Avos Dilhevia, the "true Demon King," Launches His War
Avos Dilhevia steps onto the scene and confronts both Anos and Diego in the castle, and is powerful enough to hold them both off. He wants the great hero sword, Evansmana, and reaches out to claim it, but Diego points out that no demon could draw a Hero's sword. To his astonishment, Avos does just that. War is coming, and Avos is ready to spill a lot of blood. He clashes with Anos briefly, then vanishes from the scene. Elsewhere, Diego projects himself over the human capital city and warns his fellows that a demonic invasion is coming, led by Avos Dilhevia, and he rallies all of humanity's defenders. Elsewhere, Avos has a similar message for his countrymen, and he has three of the Seven Elder Demon Emperors by his side. At last, the human realm will be crushed, and Avos claims that he had been wrong to spare the humans 2,000 years ago. It is time to correct that "mistake."
Anos isn't too pleased, but he does have a plan in mind. He gathers his fellows, from the Unitarian Club to the Necron sisters to Ray, and of course, the four Elder Demon Emperors loyal to him. He's going to get in between the clashing armies and ensure that no blood is spilled, and that will buy Anos enough time to confront Avos personally and put a stop to him. As the plan proceeds, Sasha and Misha fight as a united front against a battalion of Avos' soldiers, while Ray and Misa face another battalion elsewhere. Anos' Elder Demon Emperor fellows neutralize Avos' own, and Anos is free to face Avos one-on-one in a large field, hemmed in by smoky magical barriers.
Avos Dilhevia, the Demon... Hero?
Anos and Avos fight again, and Anos shows off a seashell necklace from the human realm. This prompts Avos to remove his helmet, revealing the face of Ray Gransdori beneath. Anos realized that something was wrong when Ray, supposedly a newcomer to the human realm, recognized human jewelry by name, but he can't be the reincarnation of Shin, because Shin would never lie to him. So, who is he really? Ray/Avos explains that he is a Hero reborn as a demon, which is what allowed him to take Evansmana. Ray isn't the reincarnation of Shin, but of Kanon the Great Hero, and he fused six of his seven sources with the Elder Demon Emperors, excepting Melheis. Otherwise, he'd give himself away as Kanon, walking around with seven sources.
Kanon/Ray/Avos agrees with Anos' assessment about the human realm, and he says that the humans of 2,000 years ago were too weak. He intends to wage war on the human world and destroy it, ruling it as the one true Demon King, or rebuild it, stronger than ever. Anos won't let either scenario that happen.