You do not just become an elite member of any organization. That is proven true in the series Demon Slayer (Kimetsu no Yaiba). When joining the Demon Slayer Corps, immense preparation is needed. Then the participant needs to take the Final Selection Exam.
Depending on the skills and abilities of an individual, preparation can take some time. Tanjiro took 2 years to prepare for the exam while Mitsuri only took six months to prepare. Having a mentor who knows about Demon Slayer Corps could be an added benefit.
When joining the Demon Slayer Corps, aside from being able to avenge your family from demons, you also get a salary, an ore for your sword, a talking bird for communication, and a standard uniform. Salary and other benefits increase as you rise in rank. The likes of Gyomei and Muichiro were able to rise in rank in just two months but some would take years before they can rise in rank.
The uniform provided to the members of the Demon Slayer Corps is made of lightweight material that is waterproof and fireproof. This material is known to be resistant to the attack of lower-level demons. They are also given Nichirin Swords which are forged from a special ore that constantly absorbs sunlight. Higher-rank demons can only be decapitated by the Nichirin Swords. The special quality of the sword allows the user to yield it along with their breathing style.
Members of the Demon Slayer Corps are also given Kasugai Crow for communication. Kasugai Crow is a talking bird. These birds are the one who delivers the mission of the demon slayer. All this equipment is provided to whoever passes the Final Selection Exam and becomes a part of the Demon Slayer Corps.
Each uniform of demon slayer has its back engraved with its rank. Ranks were designed for the leader, Ubuyashiki, to determine who will be sent, which group, for a certain demon that is terrorizing a certain region.
If Upper or Lower rank demons are involved, the Hashira, which is the Elite group of demon slayers will be the one who will be handling the situation. Ranks are shown at the back of the hands of the members. There is a password they need to say for the ranks to appear.
Demon Slayer Corps Ranks
This is the entry-level demon slayer. They are the ones who just joined the group. They are the ones who are sent for lowest-rank demons. They are also paid 200,000 Yen.
They are the elite members of the Corps and they can demand how much they can get paid.
Not much is known about the ranks in Demon Slayer Corps. Even the promotion, does not follow a certain order. After Tanjiro and his friends defeated the Spider Demons in the Natagumo Mountain, they were promoted to Kanoe. To be promoted to Hashira, you need to kill 50 demons, and another demon belonging to the Upper or Lower rank while you are a Kinoe.
It is not only the Demon Slayer Corps that has ranks, the demons also have ranks. Muzan would turn humans into demons depending on his whim. How they would be able to join the Upper or Lower rank would depend completely on their effort.
Upper and Lower rank demons can share their blood with humans and transform them to be demons, By joining the ranks of demons, you need the blood of the Demon King Muzan. If you do not receive blood from him, then you cannot be part of either the Upper or Lower rank.
Demons are known to gain more power the more humans they consume. It is also by harming other humans that one can get the attention of Muzan. In the history of demons, and looking into their past, they all share the same story, they had either killed or dangerously harmed another human.
The more brutal you are with humans, the better since you will easily get the attention of Muzan. When Doma found Gyutaro nursing his sister’s burned body, Doma was very clear with instruction as he shared his blood with them. He told them that they need to attract the attention of that man so they could share blood with him.
This instruction was proven to be correct as when Gyutaro and his sister Daki haunted the Red Light District, they only ate the finest. Even after rising to the rank of Upper Moon 6, they still decided to reside in the Red Light District. Upper-Rank Demons are bad news to any demon slayer, even to the Hashira.
It was noted in the series that several Hashira had been consumed by demons when they come face to face with them. Even during the Infinity Castle Arc, with the full force demon slayers attacking Muzan, the Upper Moon, and lower rank demons, some of the Hashiras were not able to survive and were eaten by the demons.
The sheer difference in strength between the Upper Moon, Lower Moon, and ordinary demons can easily be distinguished by the level of demon slayer attacking them. Upper Moon is the strongest of demons. In the Infinity Castle, during the Rehabilitation Arc where Muzan was reprimanding the Lower Moon, he stated that it had been over a century since anybody from the Upper Moon was replaced. The Lower Moon however kept on changing.
It can also be seen how Giyu easily defeated Rui but had difficulty when faced with Akaza. Upper Moon demons are ranked from 1 to 6. Upper Moon 1 is the strongest and Upper Moon 6 is the weakest. For Lower Moon, it is the same.
There is Lower Moon 1 being the strongest and Lower Moon 6 being the weakest. Lower Moon was disbanded by Muzan by killing the member, sparing only Enmu and giving him the chance but he still lost in the Mugen Train when he faced Kyujuro and the group of Tanjiro.
Ranks for both the Demon Slayer Corps and the Demons are important. For the Corps, it is to match the ability of an individual with the demon they are facing, and this way, they can reduce the loss they have. As for demons, it is so Muzan would know which demon he can send to do his bidding.