To pass Final Selection, one must survive for seven days on Mt. Fujikasane, where demons captured by the Demon Slayers have been imprisoned. So begins the battle for survival between the young swordsmen and the demons. Armed with the breathing techniques and stances he learned from Sakonji Urokodaki, Tanjiro cuts through demon after demon. His two years of training have not gone to waste. But just then, a morphed demon appears out of nowhere.
After a final spar with Sabito, Tanjiro has successfully attacked first and made the first strike. After slicing his mask in two, Sabito and Makomo are relieved at his triumph, commending his success before disappearing. The slash, that Tanjiro believed had reached Sabito’s mask, has actually sliced the boulder he was tasked with in half.
Tanjiro realizes that his success was due to him finding his Opening Thread, which is a scent he detects and follows to help align the path of his sword to his target. Still in shocked at his accomplishment, he is suddenly met by Urokodaki, who also sees his task finished. He reveals he had no intention of sending him to attend Final Selection, unwilling to see more children die. He was certain the boulder was impossible to slice but is taken aback by his triumph and commends the boy, calling him “a remarkable kid”. He pulls Tanjiro into a hug and asks he come back alive from Final Selection.
Back at Urokodaki’s hut, Tanjiro is shocked by the large amount of food being cooked; Urokodaki sees this as a celebration of his training paying off and tells him not to be shy. As he eats, Urokodaki internally voices that he has nothing more to teach him, and that he will soon enter a world of hardships. For now at least, he can rest easy. While Tanjiro cuts his long hair, Urokodaki asks if he enjoyed the hot pot prepared for him, to which Tanjiro acknowledges his delight. He informs him that just like humans, demons eat to gain strength, and that a demon’s power is proportional to its number of devoured victims.
Some devour humans to gain power, transform themselves and even use strange spells. Once his sense of smell sharpens, he will be able to determine the number of victims a demon has eaten. Afterwards, Urokodaki provides him with a fox mask made by himself, with a charm to protect him from harm.
In the morning, Tanjiro prepares to leave for Final Selection. Entering Nezuko’s room, he is saddened to see her still asleep and grabs her hand gently, telling her he will return no matter what. Urokodaki tells the boy he has no worry, since he will take care of Nezuko while he is away. Bidding him goodbye, Tanjiro tells his trainer to say hello to Sabito and Makomo for him. Stunned by hearing their names, Urokodaki wonders how Tanjiro knew the names of “those dead children”.
By nightfall, Tanjiro has reached the foot of Mount Fujikasane, becoming amazed at the numerous wisteria flowers of the forest. Walking up the staircase to the meeting area, he is surprised to see numerous people his age also in attendance, all of them hoping to survive. The applicants are attended to by a pair of twins speaking as one. They thank everyone for joining and inform them of their goal. The forest contains demons imprisoned in the mountain, thanks to the wisteria around the forest trapping them in, since demons despise wisteria. The end goal is to survive for seven days in the forest to pass Final Selection.
During the first day, Tanjiro has nothing but staying alive in mind, as he runs around the forest. He heads east to ensure he can reach sunlight but quickly detects a scent. Unsure of the location of the demon, he is answered when it leaps high above the forest and slams down into the ground, the impact forcing him back. Another demon emerges and clashes with Tanjiro, who manages to parry its claws but is launched back by the attack’s force. The two demons argue over who gets to kill and devour Tanjiro first, causing both of them to attack him at once. They knock Tanjiro back but he quickly regains his composure and begins to breathe deeply.
Using his past knowledge, he finds the opening thread and uses Water Breathing, Fourth Form: Striking Tide, successfully killing the two demons in one slash. As he praises himself for not letting the lessons go to waste, he remembers that his sword is the key to his success; Urokodaki had explained that demon slayers wield a special weapon call Nichirin Swords. As he prays momentarily, he is disgusted by the sudden rotting smell in the air. He hears another applicant screaming in terror and yelling of his regret in joining; Tanjiro sees the commotion but becomes horrified at the sight of an immense, grotesque looking demon.
In the forest where Tanjiro trained, at the site of the sliced boulder, Sabito and Makomo converse about the boy they had taught. Makomo, with a worried expression, asks if Tanjiro is able to beat “that one”. Sabito answers with uncertainty, saying it was never enough and that she knows it. The applicant is perplexed at the unannounced appearance of a morphed demon in Final Selection. The giant demon, made up of several green hands, has another dead applicant in his grasp, before opening his mouth and dropping the young man inside to devour.
As the applicant and Tanjiro watch in horror, the demon gains strength and grows larger. When the applicant attempts to flee, the demon meshes his arms into long appendages and grabs the fleeing boy. Before he can be devoured, Tanjiro, seeing the demon, composes himself from the initial fear and speeds forward to save him. Saying that unlike last time, he isn’t powerless anymore, he uses Water Breathing, Second Form: Water Wheel and cuts off the demon’s arms.
The demon sees his fox mask and becomes delighted, as “Another little fox has come to me”. When Tanjiro wonders what it means by another, the demon asks what year of the Meiji Era it is now. When Tanjiro answers it is now the Taisho Period, the morphed demon becomes infuriated and scratches himself in frustration, lamenting that time has now passed into a new period while he is still imprisoned. When it screams Urokodaki’s name in anger, Tanjiro asks how it knows his trainer. The demon answers by saying that it was Urokodaki who had imprisoned him on Mount Fujikasane 47 years ago. Tanjiro is surprised to learn it had lived for so long, while the applicant claims that no demon on Final Selection is that old. To this, the morphed demon states that while trapped in the forest, he has eaten 50 applicants of Final Selection, adding that he has personally devoured 13 students of Urokodaki.
As Tanjiro hears this in shock, the demon gloats about two in particular: one was a boy of strange hair color and was the most powerful of the ones he had faced, and another was a petite girl who didn’t possess much strength but was extremely agile. Horrified to learn that Sabito and Makomo were killed by this demon, Tanjiro reminisces that on his time training, he saw and spoke to them. The demon goes on by saying that he recognizes the texture of the fox masks as the ones on Urokodaki’s own. Mocking the trainer’s warding masks, he gloats about saying that they never worked and that Urokodaki might as well have killed his students himself. As Tanjiro listens, the morphed demon adds that when he told Makomo this, she flew into a rage and lose control of her emotions, leading him to rip her apart.
Filled with rage, Tanjiro attacks head-on, driven by intense emotion. Sabito, sensing that Tanjiro is attacking erratically, tells him to calm down and even out his breathing. When he attempts to slice directly in front of the demon, an arm punches him from the side, sending Tanjiro hurtling hard into a tree and breaking his warding mask. Seeing the unconscious Tanjiro about to be eaten, the applicant he saved decides to move on and and flee. As the morphed demon moves in to eat him, he gloats about how Urokodaki must feel that another student of his isn’t returning.
Before Tanjiro can be grabbed, he is suddenly visited by a vision of his brother Shigeru, begging him to wake up. He regains consciousness in time and narrowly avoids getting taken, to the demon’s shock. Claiming he can now have some fun in battle, it grows multiple arms and attempts to grab Tanjiro, who runs throughout the forest and slices them off. Tanjiro realizes they grow back quickly, while the demon tells him that cutting his neck is the only way to kill him, remembering that even Sabito had failed to do so and was killed.
Stopping in his tracks, he declares that to prevent more lives being sacrificed, he needs to kill the morphed demon. Tanjiro charges head-on once more; he detects a scent from underground and leaps upwards, while arms sprout from the ground to grab him. Seeing him in mid air, the demon morphs its arms into one long appendage to grab Tanjiro. A fearful Makomo worries that Tanjiro too will be killed by the morphed demon. While Sabito answers that it isn’t fully certain if he can win, there is one indisputable fact; Tanjiro has sliced the largest boulder of all.
Using his forehead, he head butts the arm away, surprising the demon. As he runs down its arm towards its head, Tanjiro breathes in and empowers him for an attack. When more arms sprout to get him, he slices them all and lunges forward. Believing he will fail, the demon isn’t frightened and thinks that its neck is too tough to slice. Tanjiro uses his Water Breathing and successfully decapitates the demon with First Form: Water Surface Slash.
Characters in Order of Appearance