El jugador más fuerte del MMORPG de moda, Cross Reverie, es un marginado sin ninguna habilidad social. Cuando un día se despierta en el mismo mundo del MMORPG y descubre que lo han invocado allí, notará que sus poderes del juego siguen intactos. ¿De verdad es eso Cross Reverie? ¿Y quiénes son las dos chicas que lo han invocado?

Diablo y sus compañeras acuden al gremio de aventureros a registrarse y medir su nivel.

El gremio de aventureros tiene una nueva misión especial en la que solicitan a Diablo, pero parece ser una mera compensación por parte de la Asociación de Magos por lo ocurrido con Galluk. Rem no quiere aceptar tal consideración.

Mientras los caídos asaltan la ciudad, Diablo se enfrenta a su líder en las puertas para que no pasen. El problema viene cuando se descubre que ya había uno infiltrado en su interior, y tanto Rem como Celes están en peligro.

Con Shera en peligro, el héroe de la ciudad encarga la peligrosa misión de acabar con los elfos que acechan en el bosque, pero a los incautos que acepten los acompañará un caballero imperial.

Los protagonistas se cruzan con un mercado de esclavos donde podrían aprender a quitar a Shera y Rem sus collares mágicos.

Keera llega para hacer a Shera la pregunta definitiva sobre si quiere volver con él o no, pero pese a la convicción de la elfa, algo cambia en el último momento.

Diablo se enfrenta al hermano de Shera y su poderosa invocación, pero detener la guerra con los elfos puede ser algo mucho más complicado que vencer un duro combate.

Edelgard reaparece buscando a la señora demonio sellada en Rem, pero llega con una propuesta. Mientras, un nuevo enemigo de la iglesia ortodoxa se aproxima a los protagonistas.

Edelgard prepara el ritual para que Diablo resucite a la señora demonio que duerme en el interior de Rem, pero el resultado desafiará las expectativas de todos los implicados.

Una traición desencadena una serie de acontecimientos destinados a despertar por completo el poder de Klem, pero sus amigas quieren que siga siendo la chica inocente que adora las galletas.

Diablo se enfrenta a Krebskulm, quien en su forma completa amenaza con destruir la ciudad por completo. La intervención de sus amigas para intentar calmarla puede ser la solución, pero ¿razonará su antigua compañera?

Diablo, Shera, and Rem head out to the plains to test out new magic. While using said Flight Magic, Diablo spots the light of magic energy rising up from deep within the forest, so he makes haste towards its source. However, his spell gives out half way, and he goes plummeting down! When he lands, he finds the Head Priest, Lumachina under attack from the Paladin, Gewalt.

Diablo and the others leave Faltra and arrive at Zircon Tower. There they meet an adventurer, Horn, who talks to Diablo about a new dungeon that has appeared — a dungeon that Diablo suspects is the one he created. Meanwhile, Lumachina gets into an argument with a man claiming to belong to the Paladin Brigade who kicked aside a woman carrying her baby…

Lumachina realizes that Battuta is conducting a large scale curse, threatening the lives of others, but he puts her and Rem to sleep. The two later awaken in an underground space where believers are conducting the ritual. After Horn tells them of Lumachina and Rem’s capture, Diablo and Shera take action to rescue them!

Diablo and the others were heading to the dungeon to obtain the hidden treasure that can cure the Death Knell Disease when Laminitus and her army surrounds them and attacks. Their party manages to reach the entrance to the dungeon, but there are now six marks on Lumachina’s body, and it’s said the victims of the Death Knell Disease will die once there are nine marks…

After rescuing Horn, Diablo learns of Horn’s secret. Meanwhile, Shera, Rem, and Lumachina make progress through the dungeon and reach the twelfth underground floor. When Rem opens the door, they find the man pursuing Lumachina — Gewalt. To make things worse, a Large Black Dragon appears with a terrifying blast of wind!

Diablo resolves to return to Zircon Tower at once after learning the city was under attack by the Demon Lord Army. Meanwhile the desert becomes a battlefield as Laminitus and her soldiers wage battle against the Demon Lord Army's Commander, Varakness. Laminitus struggles against the overwhelming might of the Fallen, and just as the final blow is about to be dealt to her, Diablo appears with a flash.

Lumachina asks Diablo to accompany her to the royal capital, so he decides to stop by Faltra City on the way. Diablo's group is worried about Klem and Edelgard after such a long time apart, and Sylvie informs them that they're at a bakery. Apparently the Fallen, Edelgard, had started a part-time job. Curious, Diablo and the others go to investigate...

Diablo and his group arrive at the royal capital, Seven Wall, but the guards stop them at the gates. That explosive situation is resolved by the imperial knight, Alicia. She was awaiting their arrival and leads the group to an inn. That night Diablo reveals to Alicia that the church is out to kill Lumachina...

Diablo and the others are locked up in the sanctuary by Vishos and kept apart from Lumachina. Meanwhile, Horn managed to escape, but she's torn between her desire to flee all by herself and her desire to help her friends. That's when Babalon, the Level Up Goddess that resides within the Holy Grail, appears before Horn.

The magic weapon, Europa, God of Destruction, appears from underground and attacks, damaging Diablo. Since its attacks aren’t magic, he can’t reflect them with his Demon Lord’s Ring, and Europe’s barrier keeps his attacks from reaching it. “There’s something I want you to do.”—Diablo seeks Lumachina’s aid while barely avoiding the weapon’s attacks, and…