Fortunately, Zenitsu somehow survives Daki's attack but struggles a lot being trapped beneath the ruins of the fallen house.
It's confirmed that Sanemi Shinazugawa, Inosuke Hashibira, Zenitsu Agatsuma, and Giyu Tomioka have all managed to survive the fight, but the same can't be said for Tanjiro.
Through sheer will and anger, Zenitsu was able to overcome his cowardice and stay awake in battle against demons, shown during his bout with Kaigaku and Muzan, especially in the fight with the latter in which he refused to give up and persisted despite being enervated and injured.
He committed seppuku when his former protégé Kaigaku defected to gain the powers of a demon, According to Zenitsu, his death proved to be slow and agonizing since no one could cut off his head while he bled out.
Legacy. Following the battle against Muzan, Zenitsu would live alongside Tanjiro, Nezuko and Inosuke. At some point he would marry with Nezuko and start a family that would eventually yield great-grandchildren in the present day, Yoshiteru Agatsuma and Toko Agatsuma.
Zenitsu doesn't die in Demon Slayer. In fact, he kills one of the Upper-Rank Demons and works with Tanjiro and the other Demon Slayers in the fight against Muzan. Sometime in the future, Zenitsu marries Nezuko and starts a family with her until their line reaches the present day.
But the crowning moment of his achievements is when he epically slices off Daki's head and makes a run for it—after all, she won't die until her brother's head is also sliced. Unfortunately, Gyutaro spots Inosuke and stabs him right through where his heart should be with a sickle imbued with deadly poison.
However, unlike many other characters, Nezuko will not die at the end of the series, but will revert to her human form during the Final Battle arc.
9 Zenitsu Agatsuma Swiftly Defeated Kaigaku With A New Technique. Kaigaku was originally a disciple of Jigoro Kuwajima along with Zenitsu. Kaigaku was considered the more talented swordsman for years, which made him look down on Zenitsu. Unwilling to die or to become co-successors with Zenitsu, Kaigaku became a demon.
Nezuko Kamado
Zenitsu also protects Nezuko multiple times when she is in danger, evident during Zenitsu's first meeting with Inosuke Hashibira and the battle against Enmu in the train. Eventually Zenitsu and Nezuko would marry and start a family as evidenced by their descendants.
Demon Slayers are known for their strength and bravery in battle, but not Zenitsu. Despite his cowardice, he's one of the strongest in the series. The life of a demon slayer is one of hardship.
Zenitsu mastered the first form to its full capacity but failed to learn the rest. However, the first form itself is extremely difficult. With his master gone, Zenitsu can no longer learn the remaining five forms. Therefore, during his fight with Kaigaku, an Upper Moon Six, he created a 7th form.
In the beginning of the series, Zenitsu is seen as a weak person who doesn't seem capable of much until he is asleep. In his sleeping state he awakens an extraordinary power that makes him an extremely powerful and skilled swordsman.
After the final battle
It is confirmed in the Volume 23 extras that Inosuke and Aoi did eventually end up together and that they have two great-grandsons, one of which is Aoba.
Tanjiro does not die in Demon Slayer though he nearly gave up the ghost in grueling battles against demons such as Rui and Daki. Even when he is severely wounded in his fight against the Demon King named Muzan and on the verge of death, he is brought back to life.
5 Hashiras who end up dying in Demon Slayer (and how it happens) Demon Slayer has showcased many characters that vary in personality, strength, and overall combat abilities.
After various battles within the Dimensional Infinity Fortress the remaining Upper Moons are killed by the hands of various Demon Slayers. The last member, Upper Moon Four Nakime, ends up being killed by Muzan Kibutsuji himself to stop the Dimensional Infinity Fortress from being controlled by his enemies.
Kaigaku realizes that Zenitsu is much more versatile and skilled with his swordsmanship than before. However, he still believes that no matter how much Zenitsu trains, he can never defeat an Upper Rank like him. Zenitsu then is slashed by Kaigaku with the Thunder Breathing, Second Form: Rice Spirit.
Towards the final arcs of the manga, Tanjiro is mortally wounded and dies during a fight with the Demon King Muzan. Though Muzan is also seriously injured, he uses the last of his powers to turn Tanjiro into a demon.
The “Swordsmith Village” arc ended with the major reveal that Nezuko, unlike every other demon, can't be killed by sunlight, which then put her at the center of the final arc due to Muzan wanting to eat her to obtain that same immunity and become truly immortal.
Yet, for some reason, Tanjiro Kamado, the series' protagonist, never becomes a Hashira. Demon Slayer's protagonist Tanjiro Kamado starts out as an ordinary boy but has his entire life turned around after his family massacre.
Nezuko would practically be unstoppable in the series for the following reasons: Nezuko has conquered the sun, meaning she can eat humans both daytime and nightime. Meanwhile, other demons can only eat humans at night. After immunity to the sun, Nezuko would regain her intelligence and speech when she was human.
The last member, Upper Moon Four Nakime, ends up being killed by Muzan Kibutsuji himself to stop the Dimensional Infinity Fortress from being controlled by his enemies.
1. Gyomei Himejima. Gyomei Himejima, the Stone Hashira, is the strongest Hashira in the Demon Slayer corps in terms of strength and swordsmanship. He is the only person who uses spiked flails and an axe instead of standard swords to kill demons.