How Not to Summon a Demon Lord

Takuma Sakamoto, a reclusive gamer, gains notoriety in the MMORPG Cross Reverie under the title of Demon Lord, known for his exceptional skill and powerful equipment.

Diablo wakes up to find his hands transformed and follows Shera and Rem to the Adventurer’s Guild to register. Shera is recognized as a level 30 Summoner, but Diablo's power level is beyond the guild's ability to measure.

Emile, a warrior known for defending and supporting women, confronts Diablo in a battle.

Rem, Celestine, and Emile face challenges during an unexpected assault by Gregore, while Diablo and Edelgard engage in a tense confrontation on the Bridge of Ulug.

Diablo is approached by Galford, the ruler of Faltra City, who asks for his help in averting a potential war after the Kingdom of Greenwood demands the city surrender Princess Shera.

Unsuccessful in meeting Greenwood's demands, Diablo and the girls travel to a slave market in an attempt to uncover the magical properties behind the Enslavement Collars.

The day after Prince Keera's visit, Shera unexpectedly says goodbye to Diablo as they work on potions, leaving him distraught and retreating to an inn, overwhelmed by regret. Rem is concerned by Diablo's sudden negativity.

Diablo confronts the Force Hydra, a powerful monster summoned by Prince Keera, in a battle that tests his strength against an unfamiliar foe.

Alicia returns to the Imperial Capital to deliver her report on the conflict between Faltra and the Kingdom of Greenwood, where she meets the Paladin, Saddler.

Rem reveals that the soul of the Demon Lord Krebskulm is sealed within her, and Diablo's party sets out for Starfall Tower to confront Edelgard on the night of the Demon Lord's resurrection.

Diablo's group returns to Faltra with the recently resurrected Klem. While visiting Celestine, Rem and Klem become separated from Diablo and Shera, as Alicia inadvertently leads them in the wrong direction.

Alicia's betrayal awakens the Demon Lord Krebskulm, leaving Diablo to confront Klem as her anger takes hold. Shera hurries to aid Rem, while Edelgard leads an army of the Fallen toward Faltra, setting the stage for a climactic battle.

Diablo, Shera, and Rem travel to the plains to experiment with new flight-based magic. While in the air, Diablo notices a magical light emanating from the forest and attempts to investigate, but his magic fails mid-flight, causing him to crash. He awakens to find Head Priest Lumachina being attacked by the Paladin Gewalt.

Diablo and his companions travel to Zircon Tower, where they encounter an adventurer named Horn who reveals information about a newly appeared dungeon, which Diablo believes he may have created. At the same time, Lumachina gets involved in a conflict with a man who claims to be part of the Paladin Brigade after he disregards a woman carrying an infant.

Lumachina discovers Battuta is carrying out a dangerous large-scale curse and attempts to stop him, but she and Rem are put to sleep. They awaken in an underground chamber where a ritual is being performed. Upon learning of their capture, Horn alerts Diablo and Shera, who decide to mount a rescue mission.

Diablo and his companions attempt to retrieve a treasure from a dungeon that may hold the cure for the Death Knell Disease, but they are ambushed by Laminitus and her forces. Though they manage to reach the dungeon entrance, Lumachina is found to have six ominous marks, with rumors stating that those afflicted with nine will perish.

Diablo rescues Horn and discovers a hidden secret, while Shera, Rem, and Lumachina advance to the twelfth floor of the dungeon, where they encounter Gewalt, the man hunting Lumachina, and a menacing Large Black Dragon.

Diablo decides to immediately return to Zircon Tower after discovering that the city has been attacked by the Demon Lord Army. In the desert, Laminitus and her forces engage in battle against the army's commander, Varakness, facing overwhelming odds. Just as Laminitus is about to be defeated, Diablo suddenly arrives to aid her.

Lumachina requests Diablo's company on a journey to the royal capital, prompting a stop in Faltra City along the way. Concerned about Klem and Edelgard after an extended separation, Diablo learns from Sylvie that they are working at a bakery, where Edelgard has taken on a part-time job. Intrigued, Diablo and his companions decide to visit and investigate the situation.

Diablo and his companions reach the capital city of Seven Wall, where they are halted by guards at the entrance. Imperial knight Alicia intervenes, having expected their arrival, and guides them to an inn. Later that evening, Diablo informs Alicia that the church intends to eliminate Lumachina.

Diablo and his companions are imprisoned in the sanctuary by Vishos, separated from Lumachina. Horn escapes but struggles with whether to leave on her own or return to help her friends, only to be confronted by Babalon, the Level Up Goddess from the Holy Grail.

The ancient weapon Europa, known as the God of Destruction, emerges from underground and launches an assault on Diablo, whose defenses are ineffective against its non-magical attacks. Struggling to avoid Europa's relentless assault, Diablo requests assistance from Lumachina.