Hakuto Kunai

After 15 years the MMORPG Infinity Game is shutting down. The games creator, Akira Ono, suddenly finds himself summoned into the New World as his character, the Demon Lord Hakuto Kunai. He encounters an injured girl fleeing from a demon king Greol, which he easily defeats. The girl, Aku, explains they are in the Kingdom of Holy Light whose people worship the Holy Church and the angel Cherub. As these are not parts of the original game, Kunai reasons that someone in the New World must have tried to summon a real demon lord but accidentally summoned him. Aku tells that she is an orphan cast out by cruel villagers as a sacrifice to Greol. At a nearby shrine, Kunai finds the mages who summoned him were already killed by Greol, and the shrine's Idol(Angel Throne) cannot send Kunai home as this would contradict the wish that summoned him. Instead, it gives Kunai a magic ring before turning into dust.Kunai plans to find another shrine idol, hoping a similar being to the one that summoned him could send him back home, Aku who had been sent as a sacrifice to Greol joins him.

Kunai is attacked by bandits who mistake him for associates of Holy Maidens. This is interrupted by Luna Elegant who sought to subdue the demon lord, Luna forces the bandits to retreat while Kunai realises he can be injured by Luna's magic. Irritated by her arrogant, childish attitude Kunai defeats her soldiers then punishes her by spanking her repeatedly and stealing her money. Upon reaching the city, Kunai uses Luna's money to rent a room at an inn and buys Aku food and new clothes. Later they go dining together, but an embarrassed and furious Luna catches up to them to demand the return of her money, but is forced to calmly join them for dinner when threatened with a second spanking. She later insists on sharing their room since it was paid for with her gold.

Luna's older sister, Holy Maiden Killer Queen, arrives in her war chariot with the intent to drag Luna home. Luna and Queen bicker while an army of Satanists, believing they failed to summon the Demon Lord, plan to kill both Holy Maidens using a miasma sludge sealed in a box called Hades.

The satanists then attacks and Kunai realises the satanists wear the same robes as the ones who summoned him. As the satanists unleash Hades to weaken Luna and Queen, Kunai's ring tempts him to murder the Maidens but Kunai refuses. The ring paralyses him, forcing him to swap into another of his Infinity Game avatars, Zero Kirisame, at the cost of Zero controlling himself. Zero defeats the cultists and Queen instantly falls in love with him after he treats her like a woman instead of a warrior and decides to make him her husband. Zero leaves and turns back into Kunai who is mortified at ever having created such an embarrassing character. Luna decides to continue travelling with Kunai and Aku.

While travelling aboard Luna's carriage, Kunai disguises Luna as a schoolgirl so she won't draw attention. Two bounty hunters, swordwoman Mikan and cross-dressing mage Yukikaze, are in the area hunting sand wolves for their bounty, but the pack is too large and they flee. Kunai, who happened to be nearby, defeats the wolves for skill points.

Kunai notices Aku's leg has healed badly, causing her to limp. He uses his skill points to summon one of his NPC aides, Kirino Yuu, a doctor and scientist who, despite being a genius, has an unfortunate sadistic streak and a fetish for young boys. Despite the possibility of Yuu going rogue, Kunai summons her anyway and finds that in this new world, Yuu is still loyal but has her own free will. Kunai decides to keep a close eye on her, forbids her from killing anyone, and discloses his situation. Using her unique skill "Hand of God", Yuu fixes Aku's leg in no time. Kunai thanks Yuu for her help and his praise causes the now self-aware Yuu to experience happiness and develop a crush on him. Later, as Aku sleeps, she gains a rare survival skill called "Heroine".

Kunai and the others visit Luna's province, specifically Rabi Village, which is extremely run down as Luna has been letting the Holy Church manage it for her. Kunai suspects the Church deliberately gave her the least valuable territory to keep her out of the way. He decides to improve the village by adding a hospital and hot spring. He removes the useless Church manager and learns the village is populated by demi-humans called Bunnies, whom the Church consider inferior. The Bunnies are struggling to farm the poor quality soil, so Kunai uses skill points to provide an unlimited source of water and better fertiliser.

After leaving Rabi Village, Kunai, Luna, and Yu hold a feast for Aku at the high-class restaurant Artemis in the kingdom's capital to celebrate her leg being healed. They are joined by Ebifry Butterfly, a central figure of nobility in the kingdom who Luna explains through Kunai's telepathic messaging is a powerful social figure with many connections through the kingdom. Kunai decides to attempt to gain her trust, and as he negotiates with her and tells about his improvements to be done at Luna's Rabi Village, the surrounding area comes under synchronised attacks by the Satanist Cult. Kunai tells his party to remain calm and stay in the restaurant while he takes care of the trouble. The Satanists summon a mid-tier demon called Carnival. Kunai easily defeats Carnival and the populace cheers, recognising him from posters as the Demon Lord.

The surviving satanists regroup and summon a demon prince Oluit as their last resort, who lays waste to all the combatants and destroys Angel White's holy barrier. Tron a half-demon is ordered by Utopia prior to the battle to fly in and dump the Hades miasma onto the combatants, and she does so while Mink and Queen try to hold their ground against Oluit. Kunai swaps to Zero Kirisame at the last minute and effortlessly defeats Oluit, but not before Oluit mortally wounds Tron and drains her blood to transform himself into a beastial entity. Zero save Tron from death and upon being told she forgot how to smile, encourages her to regardless of her circumstance. Zero defeats Oluit once more and strikes a victory pose, to the amazement of Tron and the bliss of Killer Queen.

Kunai discusses with Angel White, oldest of the three Holy Maidens, where he could obtain more information about Seraph, whilst Angel tries to deduce if he is still a legitimate threat to the kingdom and Church. Both parties end the conversation on seemingly amicable terms, though Angel was hiding her stress, worrying what Kunai's end goal is and wondering how he was able to tame the selfish Luna and defeat Greol so easily, whom Kunai called more like a cheap imitation than a demon king. Kunai finds he has collected enough skill points to summon a second NPC into the world and unlocked the ability to teleport to familiar locations. He and Aku visit the Church library to read up on the angels that allegedly created the world, but also to find ways to give himself resistance to magic, which did not exist in the futuristic setting of Infinity Game. A story he reads to Aku about a dog finding rare treasures in a dungeon gives Kunai the idea of such a possibility. On their way back, Tron finds Kunai and identifies him with Zero, insisting on travelling with him for saving her life. The group teleports back to Rabi Village and Kunai instantly constructs a hospital and hot springs resort, noting they are somehow still able to operate without a source of electricity, with the intent of employing the residents. He summons his aide Tahara Isami, for his fast learning capabilities and marksmanship skills, to protect Rabi Village.

Tahara is tasked with training the residents of the village and managing its upkeep, to which he thinks is too much work, but Kunai reassures he has the intellegence for it, Tahara receives a shock with Kunai's praise, but declines seeking Yuu for help. Kunai spends the night thinking how to prepare for Ebifry's arrival. One week later, Ebifry arrives at the renewed Rabi Village. She brings with him Commando Sambo, and Kunai recommends Yuu to cure his blindness. Sambo is overjoyed, and Ebifry pays Yuu with a holy lambda coin worth 100 gold coins.

Luna accompanies Ebifry to hot springs as a guide, her enthusiasm has Ebifry deduce Luna's crush on Kunai which she embarrassingly rejects. Ebifry ultimately decides to live in Rabi Village. Meanwhile, Angel learns of Ebifry's holiday in Rabi Village, thinking Kunai has manipulated her too, though Queen has no concern, saying Angel has yet to find love whilst the other two have.

Kunai leaves the village to explore the capital again, leaving a letter behind for Luna and Aku telling them to not look for him. Yukikaze and Mikan encounter him there, and Yukikaze insists on inviting Kunai to his favourite tavern Noma Noma, where everyone treats Kunai to food and drink out of gratitude for defeating Carnival. Perturbed by Yukikaze's perverted mannerisms, Kunai states he is unfamiliar with the land's customs and adventurer system. Yukikaze and Mikan tell Kunai about the Guild accepting requests and receiving fees, having monster parts sold, rankings, other guilds competing for the attention of high-rank adventurers, and mercenary work. Kunai compares this business to professional sports, and notes the relative instability of the occupation. Yukikaze also mentions the current state of wartime makes traversing the northern territories difficult. Item classification is also elaborated: Normal, Solid, High-end, Unique, Legendary, and ineffective mass-produced items. Kunai decides to travel north, and Yukikaze volunteers; Kunai reasoning his need for an experienced guide. At the Church, Angel White's anxiety reaches a tipping point. She uses her Omega Staff to teleport to Luna to rescue her, but becomes confused at the sight of Rabi Village undergoing construction. Tahara spots Angel, mistaking her for a magician hired for help, and tasks her with moving a supply of magic crystals. Angel eventually meets Luna, and is distraught by Luna's unwillingness to leave. Angel is even more unnerved at the sight of Tron, and is forced by Luna to let Kyon and Momo escort her to the baths. Believing it's her last chance to pry Luna from Kunai's influence, she explores the baths, and is surprised to find Kunai waiting for her.

Angel finds Kunai at the end of the baths, and reluctantly joins him at his insistence. Greatly embarrassed by the situation and flustered at the sight of Kunai, Angel attempts to interrogate him over his intentions for "deceiving" Luna and Ebifry. Kunai maintains his composure in front of a naked Angel and responds that they acted out of their own volition. Kunai coerces Angel to bathe and drink sake to calm her down. As the two talk, Angel becomes frustrated and breaks down over being called innocent, hardheaded, and ultimately admitting she is incompetent in managing the kingdom well on her own. Kunai gifts her an angel halo in a final effort to reassure her before leaving, noting she is the only Holy Maiden able to reflect her title. After the bath, Kunai uses his teleport skill and the two reappear back at the capital's castle, which Angel mistakes as the same miracle power she used to go to Rabi village. Further compounding this confusion, Kunai confides to Angel that the reason he wants to learn about Seraph is because he believes that Throne summoned him to this world, thinking back to the shrine idol. All of Angel's misunderstandings come together to confirm Kunai's identity as "Lucifer". As Kunai takes his leave, a smitten Angel promises to guide Kunai "back to what he once was". Some time later, Kunai leaves Tahara and Yuu to the village's care as he departs to the northern city of Rookie with Yukikaze and Mikan.