The Frontier Lord Begins with Zero Subjects

After 20 years army service, the King retires Dias, granting him Lordship of the remote, barren grasslands of Nezrose territory. Upon arrival, Dias meets the hostile Alna, a young woman whose horn glows blue when he speaks. He declares himself her ally, prompting her to lead him to Chief Moll of Onikin tribe. Moll reveals the Onikin are enemies of the King who stole the grasslands, so they hide their village with invisibility magic. Their horns can detect intent, glowing red for enemies and blue for friends. Deeming Dias an honourable idiot, Moll offers peaceful neighbourly relations, gifting him a tent, food, and two Baar (sheep), promising future trade if Dias raises a herd and hunts monsters. Dias slays forty Ghee (bison), impressing Alna. Moll explains that Dias's usefulness has proven his "manliness," making him an attractive potential husband. To Dias's embarrassment, Alna begins visiting to cook and offer village-building advice. Seeking trade supplies, Alna suggests a monster hunt. Though respecting his new "manliness", Dias faces resentment from Onikin men jealous of Alna’s affection for him. During the hunt, Dias wields his magical self-repairing battleaxe he took from a Shogun. When an Earth Dragon attacks Alna, Dias crushes it, prompting Alna to declare she will marry him.

Moll reveals the dragon is too valuable to trade entirely. In exchange for a portion, the tribe construct him a well and a private toilet. Moll advises gifting the most valuable parts to Alna’s parents, warning that as a dragon slayer, every unwed woman will pursue him if he does not marry Alna. Dias feels guilty learning Alna is only 15, 20 years his junior, and his unease deepens during their wedding. Due to their isolation, Dias worries about finding citizens for his future village. Alna discovers their Baar, Francoise, is pregnant. Because pregnant Baars can die from stress, they must move inside the tent. While this usually causes marital strife among the Onikin, Dias gladly obliges, impressing Alna. When travellers approach, the Onikin hide. The group includes Dias' former comrade Klaus and soldiers escorting Princess Diane, who offers marriage in exchange for conscripting his citizens for the new war. When Dias explains the King gave him nothing to build a village with, and that he has no citizens, Diane feels insulted and a soldier attacks. Dias disarms him and orders them away, prompting Diane to swear revenge. Alna reveals due to almost being married her horn now glows during threats against Dias as well. Klaus returns, having gotten fired to avoid the war, and asks to serve Dias instead. Alna agrees, noting his honesty made her horn glow blue.

Klaus settles in as Captain of the Guard, outfitted in Earth Dragon armour. He suspects Diane's brother the greedy second prince confiscated Dias's village funding due to the royal succession dispute. Dias discovers twelve elderly women exiled from the Kasdeck tribe to starve, and welcomes them as his first citizens, naming the settlement Iluk Village; "First Village" in the ancient Onikin language. The women's leader, Grandma Maya, is relieved by Dias’s anti-slavery stance, revealing that the current Kasdeck Lord hunts slaves for sport. Alna summons a trusted Frog-man merchant, Peijin-Do, to purchase the Earth Dragon materials. Peijin-Do explains he has two young elf twin slaves whose deceased parents paid him to protect them, but as the money has run out, he is seeking someone else to look after them. Dias takes in the twins, Senai and Ayhan. Alna reveals their names mean "Beautiful Moon" and "Holy Moon" in the ancient language, moving the girls to tears over memories of their parents. Ten days later, Kamalotz the aide to Eldan, the new Kasdeck Lord after defeating his father in a rebellion, arrives requesting a meeting. Dias reluctantly agrees, wary of Eldan's infamous harem of female slaves and the threat he poses to Iluk Village.

Dias is surprised Eldan is a victorious rebellion leader, given his youth and obesity. Eldan eagerly seeks an alliance, expressing long-standing admiration for Dias. Upon learning of Dias’s onikin wife and adopted elf daughters, Eldan reveals he is a half elephant-man whose mother was a demihuman slave. Shifting forms exhausts him, requiring constant care from his harem of loving wives. He explains that his father initiated a war upon discovering Eldan’s underground movement to free demihuman slaves, which ended in Eldan’s victory as the freed slaves vastly outnumbered his father's soldiers. Dias feels embarrassed to learn rumours have falsely famed him as a heroic slave liberator and enemy of the nobility. Still, he agrees to the alliance, and Eldan promises winter supplies to aid Dias’s growing village. That night, mercenaries led by a noble with a personal grudge against Dias attack the grasslands. Dias and Alna effortlessly defeat them, though the noble escapes. Instead of executing the mercenaries, Dias disarms them to melt their weapons for valuable steel before exiling them. Touched by his mercy, Alna reflects on choosing not to kill Dias when they first met, impulsively kissing his cheek in an embarrassing burst of affection.

Dias wants to grow crops, but Moll explains only grass survives on the Grasslands, suggesting he seek advice from the nature-sensitive forestkin. Dias decides to test an onikin method of growing herbs in potted soil mixed with bone and crushed verdant-leaf stone. Kamalotz returns with Eldan’s promised supplies, including tools and livestock. Hidden in the wagon are several small mousekin, seeking to prove their bravery by defeating the Dragon Slayer. Dias easily defeats the stowaways, and Eldan apologizes for their actions, as mousekin are an argumentative species who did not believe Eldan's promise to free them and return them to their home in the desert. Alna, having grown up in poverty thanks to her older brother, is thrilled by the horses. As Dias cultivates fields with Klaus, an anxious Senai and Ayhan ask if keeping secrets is wrong; Dias reassures them that harmless secrets are fine. When Dias's medicinal herbs wither after a single day, he is left demoralized. Senai and Ayhan consider breaking a promise to their parents. They suddenly hear a cry for help from an intelligent mousekin trapped inside a box in the storage tent.

The mousekin, Aymer Jerrybower, reveals she was boxed up as punishment by her peers for refusing to attack Dias. Recognizing her intelligence, Senai and Ayhan seek her help. They reveal they are forestkin carrying their late parents' knowledge seeds. When planted, these seeds become trees that act as gravestones and knowledge repositories. They can also help the girls generate barriers that boost plant life—though they swore to keep this power hidden from humans. Aymer suggests planting them secretly at night. In Kasdecks, rumors swirl about Dias, including claims that a monkeykin orchestrated the mousekin attack. The monkeykin is really the noble Dias defeated earlier, who holds a grudge against Dias for making him permanently impotent by kicking him in the groin for assaulting a woman. Diana marches 200 knights to the grasslands. Despite disliking mice, Alna accepts Aymer after sensing no malice. Dias is shocked when crops grow on his farm in a perfect circle instead of his neatly cultivated straight lines. A pigeonkin named Geraint brings a message from Eldan stating several dogkin wish to join the village. Dias agrees to welcome the dogkin and Aymer as citizens. That night, the dogkin arrive pursued by a Lich-anaconda. Caught off guard while asleep, Dias faces the monster with his bare hands.

After Dias strangles the anaconda, Canis, a dogkin working for Eldan, introduces Dias' new subjects: the Tibe Masti clan and their leader Marf, the Bah Senji and leader Sedorio, and the Ausun Shep and leader Shev. Canis doubts the small dogkin can be soldiers, but Dias invites her to stay and see his plan. Klaus is smitten with Canis instantly and soon turns the Tibe Masti into effective warriors while the other clans excel at farming. Diane plunders the First King’s tomb for a magic sceptre to attack Dias’s village, misinformed by the impotent noble that Dias harbours a hidden fortune and lied about his war heroics. Her aide, Prinessia, abandons her to inform Prince Richard. Richard hesitates to act; he and the King deeply respect Dias, who transformed Richard from a spoiled prince into an honourable man and earned the nicknames "Dias the Kind" for protecting civilians during war, and "Ballbreaker Dias" for the way he punished Richard's rapist brother, the impotent noble, Prince Meiser. Richard also reveals it was Meiser who stole Dias' village-building funds. Richard dispatches his subordinate Narius to retrieve Diane quietly and repay Dias. Diane uses a forged royal decree to demand troops from Eldan. Recognizing the fake, Eldan delays her and warns Dias, who shockingly replies that Eldan should let Diane attack. Before battle, Klaus and Canis confess to each other.

Diane is furious Eldan’s men refuse to fight until Eldan finishes his cup of tea, since noble etiquette states it is teatime. Meanwhile, Captain Gordon and his mercenaries also refuse to attack Dias, a widely respected figure who spared many mercenary lives during the war. Frustrated that the sceptre famed for "reducing 10,000 men to ashes" isn't working, Diane is shot off her horse by an invisible Alna, forcing her toward the Eastern Forest where Narius captures her. Narius leaves behind Prince Richard’s gold for Dias, though Alna distrusts Narius as her horn glows red and white in his presence. Eldan formally surrenders to Dias. Alna notes the sceptre was just empty of magic, so she refills it, causing a blast of dragon fire. The King imprisons Diane. Meiser frames one of his allies for his crimes, escaping punishment but losing the rest of his noble supporters. Richard is upset Eldan negotiates to pay no taxes for three years, then publicly supports Richard as the next king. This means Richard cannot oppose the tax break without seeming ungrateful to an ally, giving Eldan three years to become extremely rich. Narius is disappointed he could not retrieve the sceptre; unaware Dias now uses it to light cooking fires.