Shinigami are guardians of the souls who are going through the circle of transmigration. In ancient times, they were known as Balancers. They purify Hollows who do evil in the World of the Living and ensure the safe crossing of souls - the Pluses who have lost their way after death - by giving them a soul burial.
Shinigami are unearthly beings living in a world ruled by a different logic than the World of the Living. They possess high Reiryoku and a body of Reishi. They are invisible to those without spiritual powers.
When souls with exceptional spiritual energy train their bodies, they reach the level of Shinigami. The most talented of them become affiliated with various organizations like the Gotei 6. Sometimes, a potential Shinigami is born among the residents of the Rukongai, and in some rare cases from Seireitei.
Shinigami receive salaries, like workers in the Human World and also earn bounties for defeating Hollows.
Shinigami do not visibly age at the same rate as Humans and tend to maintain a youthful appearance for centuries. Shinigami can live for much longer than Humans, with some Shinigami over thousands of years old. While Shinigami can be injured and killed like regular Humans, it takes considerably greater injuries to kill a Shinigami than it would to kill Humans. Decapitation is the only guaranteed method of killing a Shinigami.
The process by which a Shinigami sends wandering Pluses in the Human World to Soul Society if they are good in life or Hell if their life was full of evil acts (such as murders, theft, etc.) is named Konso. Konsō is performed by using the hilt of the Shinigami's Zanpakutō, tapping the soul on their forehead and transporting them to the afterlife
When a Shinigami slays a Hollow with their Zanpakutō, they cleanse their sins. Once this takes place, a Hollow will return to its former state as a Plus and is led into Soul Society. This is called sublimation. Souls that live in Soul Society are reborn again into the Human World. Not all Hollows are sent to the Soul Society. Since Zanpakutō are only capable of cleansing sins committed after becoming a Hollow, Hollows that committed serious crimes when they were still Human are sent to Hell when they are slain.
Shinigami are responsible for governing the flow of spirits between the Human World and Soul Society. This is commonly carried out by balancing the total number of souls by moving and managing them in the Human world. All of the soul-related jobs are under their authority.
The Zanpakutō of low-ranking Shinigami are called Asauchi and do not have names, but the Zanpakutō of Shinigami of rank have names. In its sealed state, a Zanpakutō has the form of a Japanese sword. Such weapons are unique swords generated from their owner's souls. Its shape differs depending on its owner.
Zanpakutō are the trademark weapons of the Shinigami. Capable of cutting spiritual bodies, they are among the few weapons which can be used to combat Hollows. Each Shinigami carries a Zanpakutō, and each Zanpakutō is unique: the swords are reflections of a Shinigami's power and soul, and sentient beings unto themselves. The Zanpakutō's name is the name of the living spirit which empowers the sword and lends its strength to the Shinigami who wields it. These beings can vary greatly in appearance, and have their own distinct personalities, which match their owner's.
A Zanpakutō's shape and abilities are based on their Shinigami's soul. Once a Shinigami learns his/her sword's name, they can communicate with one another and grow stronger together. Zanpakutō are born with their Shinigami, and they die along with their Shinigami. Shinigami use them in battle as a reflection of their heart. When released, they can display a vibrant power. They are one with the Shinigami, and they share a Shinigami's conviction. Because they are part of their owner's soul, a Zanpakutō cannot be replaced, though it will slowly regenerate if it is broken.
Depending upon the Shinigami's ability to communicate with and control their Zanpakutō's spirit, a Zanpakutō can manifest itself in two additional forms and revert to a sealed state. These two forms, known as Shikai and Bankai, are akin to upgrades for the Zanpakutō, giving it abilities far beyond those of its simple use as a sword. Shinigami usually carry their Zanpakutō in its sealed state, and activate the released forms as necessary.
Shinigami can also use the art of Kidō,a form of Shinigami combat based on advanced spells. These spells are produced with strong Reiryoku and fall into two categories: Hadō for direct attacks, and Bakudō for battle support. Kidō spells are triggered by an incantation. Experienced users can trigger them without an incantation, though the effectiveness of the spell will be diminished.
Shinigami rely primarily on Zanjutsu, the name given to their skill with the sword, and Kido to fight. After unlocking their Shikai a Shinigami enters a whole new level of power and can finally start making a name for themselves, exemplified further if they ever unlock the power of their Bankai. Shinigami use a myriad of abilities and techniques, the most out of any race, to take down their targets and arguably take the most time to mature to full strength.
The ranks of the Shinigami go as such and are detailed below.