|Hataraku Maou-sama! Light Novel Volume 15|
|Romanji||Hataraku Maō-sama! 15|
|Release Date||February 10, 2016|
|Number of Pages||312|
|Cover Character/s||Emerada Etuva, Sadao Maou, Chiho Sasaki, Emi Yusa|
|Previous Novel||Light Novel Volume 14|
|Next Novel||Light Novel Volume 16|
Hataraku Maou-sama! Light Novel Volume 15 (はたらく魔王さま！15) is the 15th book of the Hataraku Maou-sama! Light Novel series.
The Demon King finally receives training to become a fulltime employee! Meanwhile, Chiho and Emerada are facing another worldly crisis by planning a Christmas Party. Also, Gabriel makes a shocking revelation about the angels' past, while Chiho and Rika take a trip of their lifetime.
Prologue: The High School Girl and Office Lady, Welcoming the New Year Together Edit
At the start of the new year, Rika is making a visit to the Villa Rosa Sasazuka apartment with Chiho, but is stunned to learn from Chiho that everyone from Ente Isla, including the angels and even the Amanes, have headed back to Ente Isla.
Chapter 1: The Demon King, Temporarily Absent 1 Edit
Several weeks prior, Chiho has signed up to take on extra work over the Christmas holidays despite the protests of her friend Kaori. On the way home, she runs into the normally cooped up Urushihara walking alone, and over a meal Urushihara explains to Chiho that Maou, Ashiya, and he do not trust Lailah still and see her plans are full of holes. Around the same time, Ashiya visits McRonald's while Emi is working but he is strangely distant, especially when Emi asks how it's been with Rika. Apparently Rika and Ashiya have not talked for two weeks since the disastrous confession.
On the way home, Emi runs into Lailah and asks her how she met Nord. Lailah deflects it by asking Emilia whether she had her own love, causing Emi to be embarassed and stutter. Sariel, looking to visit Kisaki, encounters Ashiya and learns that Maou and Kisaki are currently at Maou's potential full time position training. Sariel demands Ashiya to let him know what is going on between Maou and Kisaki, and Ashiya ends up taking him to meet Kisaki. However Sariel refuses and they end up talking about how Sariel wants to marry with Kisaki and how it might not happen. They end up running into Kisaki and they part ways.
Continuing from the end of Volume 13, Gabriel begins talking about the tiny island nation of Nauru and uses the country's economic boom and fall into poverty to explain the situation in Heaven to the others, as the angels are starting to become and feel more useless as they have no more purpose. The others are surprised to learn there are only 5,000 angels in Heaven and even more surprised to learn that the angels actually came from another planet in another galaxy and the majority of the angels were human researchers while Gabriel was the head of security. A supernova along with a series of pandemics destroyed their planet despite their best efforts to save it, and during their research in trying to save their planet they made significant discoveries into immortality as Ignora, their leader, discovers the Tree of Life on their planet and the Sepirah children.
Chapter 2: The Demon King, Temporarily Absent 2 Edit
Emerada and Suzuno are out shopping, but Emerada is depressed. Emerada has gotten a message from Alberto back in Ente Isla that Olba's trial is causing chaos and that he needs her back now, which makes her sad as she has really liked her time in Japan. They end up buying a bunch of stuff. They run into Rika, Emi, and Shimizu Maki, a coworker of Emi and Rika's, and they end up chatting. Emerada is troubled because she knows she might never see Japan again and knows that Emi likes Japan a lot and is considering staying here. She ends up deciding to stay for Christmas and messaging Alberto her intentions.
Back home, Emerada and Emi wonder what Christmas really is and if they'll even be back for Christmas next year. Emerada teases Emi over her warming relationship with Maou and wonders about Chiho and Maou. She also gets the opinion of Nord, who tells her he just wants Emi to be happy.
Lailah tells Emi and Nord that when their homeworld was being destroyed by the plagues caused by the supernova, she (a researcher) met the personfications of Yesod and Malkuth, Kael and Shekeena, who appear to be researchers trying to help save their home world. They discovered a genotype which could help fight against the pandemic. Although the research was making progress tensions between Ignora and Sataniel, another researcher, began increasing because their discoveries were into a new type of engineering not seen on their homeworld, genetic engineering. After some investigating, Sataniel and Ignora found out that the Kael and Shekeena were not really humans, but instead a special form of human, which leads to the discovery of the Tree of Life on their planet's moon and the Sephirah children. The researchers decide to continue their research on the moon. Eventually, Sataniel and Ignora ended up getting married, and it turns out they are Lucifer's parents.
Chapter 3: The Demon King, Temporarily Absent 3 Edit
Emerada visits Chiho at work and learns that Maou is training to become a full time employee. The others find out about Emerada's plan to throw a Christmas party for Alas Ramus. They decide to figure out how to plan out the party soon. Afterwards, Ashiya catches up with Chiho and asks Chiho how Rika is doing and Chiho replies that Rika is a strong girl and can handle it. Chiho meets up with Emi and finds out that Emi wants to settle down in Japan and is tired of being a hero, especially since it appears Maou is settling down also.
The setting shifts back to Gabriel's explanation. He explains that the revolutionary discovery of immortality caused the inhabitants of their home world to fight over it as countries began to seclude themselves and begin demanding access to the research. Despite this, the researchers manage to make progress on the immortality research until one day Ignora completes it. However, around that time their research facility was attacked.
Chapter 4: The Demon King, Temporarily Absent 4 Edit
Back in Ente Isla, Alberto is complaining about everything and everyone to Heather Lumark, the Western Continent's famed general in the war. The conversation turns to Emilia and how Emilia doesn't want to come back, along with the political complications if she came back. They decide it's better if Emilia stays there in order to prevent further complications.
Gabriel continues to explain that the Sepirah children wanted to destroy the immortality technology in order to prevent the humans from getting it. Ignora managed to prevent the researchers from getting killed and Sataniel manages to fight off the Sephirah children. The researchers decide to spread the immortality gene among themselves. However, this attack leads to countries from their homeworld to assume that a war had started and thus they began to start killing each other for possession of the immortality research. Faced with this crisis, Ignora and the researchers ended up abandoning their homeworld. Ten years pass, and as they leave their solar system, they use a long range telescope to find out that their homeworld was destroyed. They ended up drifting to the Ente Isla planet, where they detect heavy magic similar to the Tree of Life, and decide to settle on a nearby planet.
Extra Chapter: The High School Girl and Office Lady, Welcoming the New Year Together Edit
Back in the present day, Rika moans about how everyone just left and how the Christmas party didn't even go on. Chiho explains that by the time the Christmas party occurred everyone had decided to leave, and at the time Chiho, outnumbered, didn't resist as they left to go fight Ignora. However, Chiho refuses to accept this now and decides to head to Ente Isla, and heads through the gate in the apartment with Rika.
Rika wakes up, confused at where she is, until she sees Emi. Emi embraces her and apologizes, saying they have to leave quickly. Emi explains they are on the Central Continent in the former Demon Fortress and even brings a dazed Rika outside. Rika ends up meeting Chiho and the others. Chiho explains that when they arrived at Ente Isla, Rika hit her head and fainted and was taken to the Demon Fortress. They meet Maou, who explains that they decided to head to Ente Isla after being convinced it was for the good of Alas Ramus and the other Sephirah children. He continues the story told by Gabriel by explaining that after the other worlder researchers arrived at Ente Isla, Sataniel wanted to live peacefully with the new humans but Ignora looked down upon the new humans and refused to be led by them.
Faced with no choice, Sataniel took his son Lucifer and fled with the Yesod fragment. In order to take back the Yesod fragment, Ignora and the researchers began experimenting immortality on the humans of Ente Isla, but rejected humans by the Sephirah began turning into demons. Sataniel along with Lailah went beserk and freed the victims and formed a demon army to resist Ignora and her forces. However, Ignora's forces were stronger and Sataniel lost his life in a battle with Ignora, and eventually his followers scattered to Ente Isla's moon, which became the Demon World.
Along with loyal allies throughout Ente Isla, Sadao and the others plan to refurbish the Demon Fortress, which is actually a spaceship of sorts, to fight Ignora, or "God", and the Heaven forces. He also casually drops in they plan to return back to Japan after the battle. But his current goal is to spend Christmas with Alas and prepare for the great battle ahead.