There is a manga adaptation illustrated by Akine Itomachi that began serialization in 2019, which is licensed in English by Seven Seas Entertainment.
The story begins with Banaza being summoned to another world in hopes that he could help the kingdom that summoned him. However, after his disappointing stats are discovered, he is dismissed from consideration in favour of someone with far better stats while Banaza ends up stranded because the portal to send him back closed. The King of Klyrode, wanting to avoid the embarrassment of a rejected hero-candidate staying around, pays Banaza to keep quiet about the situation and sends him away to Delaveza Forest to live out his life.
Or at least, that's what he told Banaza. The truth is that he sent Banaza to die in a demon-occupied forest and to expediate the process, the magic bag containing the gifts in exchange for his silence is enchanted to attract monsters and the weapons provided are near-worthless. Banaza manages to kill the first monster to attack him and levels up, upon which his stats becomes infinite. With his new power, Banaza abandons his previous name and renames himself Flio and tries to adapt to his new world.
Contains examples of:
- Black Comedy Rape: In a messed up Black Comedy scene, Hiya, a female djinn, grows an enormous penis through magic and rapes the witch Damalynas.
- Both Sides Have a Point: The humans (which includes demihumans) do have a legitimate issue with the demon races who produce malicium which are dangerous to them even if they don't mean to, with only the more powerful demons able to suppress malicium leakage. On the flipside, the demon races have a legitimate issue with the human races whose solution to the malicium problem was to oppress them.
- The Cake Is a Lie: Wanting to avoid the embarrassment of a rejected hero candidate staying around, the king of Klyrode gives Banaza money and gear in exchange for his silence and going away to a remote location. Banaza accepts this as a more or less fair trade, until he discovers the bag holding everything is enchanted to attract monsters, the provided gear is subpar, and the bag is also enchanted to return to the king after Banaza dies, proving the gifts are insincere and that the king arranged for him to die all along.
- Conscription: According to Byleri, she was forcibly recruited into the kingdom's army when they shoved a bow into her hands.
- Cooldown Hug: Fenrys gives Flio a hug to stop him from further beating up Hiya on her behalf.
- Cornered Rattlesnake: A previous Demon King pushed humans very far and they developed a powerful spell that seals the malicium circulation system in demons. The knowledge is largely lost in the present but Gholl cites this as why demon kings should be more careful in wars.
- Dangerous Forbidden Technique: Time Magic is very dangerous. Hiya explains to Flio that misuse can cause bad time discrepancies which are dangerous if left unchecked, and usage can draw the wrong sort of attention from the deities. For these reasons, she wants him to never use Time Magic again. The next time he uses Time Magic, this time to save Gholl's life, the celestial beings directly intervene and command him to stop. They are shocked when he manages to resist their power and do it anyway.
- Didn't See That Coming:
- The Infernal Four consent to Yuigarde challenging his brother Gholl not because they thought he was better, but to get Gholl to recommit to the desire of the demons to subjugate the human races. They didn't expect Gholl to simply concede his Demon King title to his brother due to him understandably, but wrongly, thinking his people have lost all faith in him.
- The Celestial Plane attempt to intervene to prevent Flio from using Time Magic to save Gholl. They are shocked that he, a mortal, is able to resist their power and do it anyway.
- Encounter Bait: Flio's Bottomless Bag that was gifted to him by the King of Klyrode is enchanted with Monster-Luring Magic as part of the king's attempt to have him killed. Flio manages to dispel it.
- Entertainingly Wrong:
- Gholl misinterprets a lot of Balirossa's actions as being more impressive than what it actually is in reality. When they first met, he considered her brave for standing up to him when she genuinely did not know he is the Demon King. In a later meeting, he is impressed by her ability to remain calm despite his presence, but it turns out she was so nervous she fainted while somehow keeping her back straight and her eyes open. There are more incidents after that, and the people around them realize that Gholl is way off in his assessments.
- Flio's party thinks the pure malicium being attacking the hot springs is due to the demon officers present bringing a magical device to do it, which is a reasonable conclusion. However, the truth is that the device is there because the Golden-Haired Hero brought it with him without knowing what it is.
- Fantastic Racism:
- In the world Flio came from, baseline humans treat demihumans as second-class citizens at best. Treating them as slaves is more typical.
- In the world Flio arrives in, there is a lot of mutual prejudice between the human races and the demonic races, enflamed by centuries of unending military conflicts.
- Forensic Accounting: The First Princess' adviser reviewed the accounting records for the period where her father and grandfather reigned, and realizes almost a fifth of the kingdom's expenditures are unaccounted for, leading to the discovery they had embezzled funds.
- Forever War: The conflict between the human races and the demon races has endured for five centuries before Flio arrived. It is roughly even as while the demon races are more powerful on average, the human races have access to the purification spell that is anathema to them and the ability to summon heroes from other worlds who come with major bonuses to tilt the odds in their favour. The tides of battle also turns depending on the competency of the various commanders on each side.
- Guilt-Tripping: In order to get Balirossa to agree to let Gholl and Uliminas stay with them after they left the Dark Army, Fenrys pretends to cry while asking if she has no heart and wants to turn her friends out into the cold. Flio lampshades this and says Fenrys might as well not even ask while Fenrys gives Balirossa a nonchalant look while the latter is going through a guilt-trip.
- Internal Reveal: Uliminas encountering Flio's party results in different revelations for different parties that the reader already knows:
- Uliminas finds out what Fenrys has been up to while she was considered missing by the demon forces.
- Uliminas also finds out Flio is the one who wiped out the demon forces occupying Delaveza Forest. Flio likewise finds out about his feat.
- Balirossa and her squad find out Fenrys is the same demon that almost killed them and they faint from shock.
- The Little Detecto: After the discovery that someone is using powerful concealment magic to disguise shoddy products as quality products, Flio creates special devices meant specifically to detect the use of concealment magic.
- Marry Them All: Soon after Gholl learns Uliminas loves him and desires to marry him despite his own infatuation with Balirossa, he decides to marry them both. Generations of the Demon King have taken multiple brides after all and he sees this as the simple solution to the love triangle.
- Mistreatment-Induced Betrayal: Discussed. The First Princess discovers Flio was Banaza, the rejected hero candidate whom her father sent to die. Combined with the knowledge that the Golden-Haired Hero tried to press-gang him into service and he has some unspecified connection to the demons, she fears that Flio might outright join the demons and the humans would only have themselves to blame.
- Morality Kitchen Sink: Broadly, the opposing factions are the human races and the demonic races, defined by whether they produce malicium or not. Both sides have people of all sorts where there are bad rulers and tyrants like King Klyrode for the humans and Yuigarde for the demons, far better rulers like the First Princess for the humans and Gholl for the demons, their subordinates who are good, evil, and everywhere in-between, ranging from only fighting each other out of duty to wanting to continue the fight out of sheer hatred for the opposing side.
- New Life in Another World Bonus: Justified. There's a reason each world in the setting rely on summoned heroes. The deities cannot just grant blessings to people on a world. Their only opportunity to properly grant their blessings is during the travel period between worlds. There is no other way for them to grant their blessings.
- Nice Job Breaking It, Hero: The Golden-Haired Hero's attempt to press-gang Flio into serving under him has severe consequences for him and the Kingdom of Klyrode. Not only does Flio refuse and use powerful teleport magic to escape, a squad of knights desert and join Flio in protest of the Golden-Haired Hero's actions. Gholl the Dark One witnesses all this and furious at what the Golden-Haired Hero did to his friends, he marshals his army to attack the Kingdom of Klyrode that very instant and the only reason they are held at bay is because the human mages manage to raise a purification barrier in time, but that is at the cost of said mages being out of commission for months, longer than how long the barrier will last, meaning the kingdom is screwed unless something changes. It was so bad that the First Princess stripped the Golden-Haired Hero's status as Hero after the fact, having had enough of him causing more problems than he solves.
- Nice Job Fixing It, Villain: Yuigarde, Gholl's younger brother, manages to make things better for their enemy Klyrode. By challenging Gholl for the Demon King title and forcing the Infernal Four into silence, Yuigarde makes Gholl think his people have lost faith in him and he simply concedes the title. As the new Demon King, Yuigarde's ability to lead an army leaves a lot to be desired, which gives Klyrode some much needed breathing room for them to recover from the damage the Golden-Haired Hero and the former King of Klyrode inflicted on them.
- No-Holds-Barred Beatdown: In their first encounter, Flio becomes so enraged when Hiya almost kills Fenrys that he brutally beats her up, and it is only Fenrys giving him a Cooldown Hug that he manages to calm down.
- Official Couple: Flio and Fenrys are established as the main couple from the first volume.
- Off the Table: Klyrode's one opportunity to ask Flio to be on their side is soon after they summoned him. After they rejected him for seemingly being unsuitable and the King of Klyrode sends him to die in exile, they ruined that one chance, especially after Flio befriends and married the demon Fenrys. Elizabeth recognizes this, and unlike her father and the Golden-Haired Hero who tried to force Flio to serve in their army, she settles for making sure Flio doesn't outright join the Demon Army after how badly he was mistreated and alienated.
- Painting the Medium: When Gholl explains the division between humans and demons, the manga adaptation neatly illustrates this by having Flio and Fenrys in one panel, but each on one page and the gutter between separating them.
- Press-Ganged: Against the advice of the First Princess, the Golden-Haired Hero suggests, and King Klyrode approves, using military force to make Flio work in the kingdom's army. Not only does it not work, it badly backfires. Flio just uses his potent magic to teleport out of there, with a squad of knights deserting the army in protest of his treatment and joining him. Gholl the Dark One is also enraged by how his human friends were treated and retaliates with military force in turn, forcing the kingdom to marshal every available mage to cast a powerful purification spell that knocks them out for months.
- Removing the Crucial Teammate: When the Kingdom of Klyrode sees that Flio's stats are average at best, he is dismissed from consideration as a hero-candidate in favour of a different hero-candidate with far better starting stats. King Klyrode then sends him to die in a distant forest and Flio finds out about the Uriah Gambit when he discovers the enchantments on the bag given to him. Big mistake. Flio turns out to be a case of Magikarp Power, and upon levelling up to Level 2, his stats reach infinite while the seemingly better hero-candidate never manages to improve his stats and turns out to be a coward lacking any proper ability to lead troops in battle, meaning Flio turns out to be the better candidate all along. The First Princess later discovers this after removing her father and his appointed hero from power when an oracle referred to him as the true hero candidate, and knowing her kingdom alienated Flio, tries to make amends. Even then, she realizes that Flio will never want fight for humanity against demons after how her father alienated him, and settles for making sure he doesn't outright join the demon side since if he does, the human races won't stand a chance.
- Sealed Evil in a Can: Hiya the Djinn of the Wellspring of Light and Dark and Damalynas, Grand Magus of Midnight are both powerful and dangerous beings from the annals of history, and when they were sealed away, they were used to seal each other. The Golden-Haired hero freeing one results in the other being freed.
- Sibling Yin-Yang: The brothers Gholl and Yuigarde are quite different. The former is a thoughtful leader while the latter is brash. The former cares about the lives of his soldiers to the point of willing to avoid taking victory if he thinks the cost in demon lives isn't worth it while the latter thinks nothing about sending them to their deaths to achieve victory at any cost even when it's clear it isn't working.
- Their First Time: Flio and Fenrys consummate their marriage in the middle of Volume 1.
- This Means War!: When the Golden-Haired Hero drives off Flio's party with his heavy-handed recruitment attempt, threatening death if he doesn't comply, Gholl the Dark One becomes furious on behalf of his human friends and marshals his forces to attack Klyrode.
- Uriah Gambit: King Klyrode sends Flio to die in a forest he knew was occupied by demon forces and gave him a bag enchanted to attract monsters and stored only with flimsy weapons.
- Wham Line: In-universe and out, people are shocked when Gholl declares he will simply relinquish the throne and title of Demon King to his brother when his brother challenges him for it.
- Wutai: The main setting appears to be a western fantasy, with names and a general aesthetic to match, but the Kunosaki Hot Spring Resort is modelled after Japanese hot spring resorts. In-Universe, it is inspired by "a mysterious island nation across far seas".
