Academy Student: Academy students (忍者学校生, Akademī-sei) make up the student body of the Ninja Academy, where they are trained and prepared for life as a shinobi. They are not an actual part of the shinobi force, as they are still in the process of mastering the very basics of the ninja lifestyle. However, they can be conscripted as part of the war potential in times of emergency.
Academy students spend their time honing the various skills they are required to have and undergoing various tests and exams to see how they progress. Besides ordinary school subjects such as history and mathematics, they are taught the basics of Ninjutsu, Taijutsu, and most likely also Genjutsu. This includes learning about chakra and how to control it, tactics, hand seals, and several E-rank techniques, such as the Clone Technique and the Transformation Technique. They are also trained in working both individually and in teams.
Eventually they are given a graduation test to see if they are ready to try and become Genin. Passing this test does not automatically grant them this title, as they need to pass a second test given by their Jōnin instructor, but they do receive a forehead protector. Those who fail either of these tests are sent back to the Academy.
Genin: Genin (下忍; Literally meaning "low ninja", Meaning (Viz) "junior ninja") are the lowest level of ninja and also the ones that display the most difference in power. When they become genin, ninja start to do their bit for their village's economy – being sent on missions that the village gets paid for. They are typically sent either on D-rank missions, which are almost entirely risk-free jobs of manual labour, or, rarely, on C-rank missions, which are a cut above that and begin to verge on real "ninja" work that have a very low possibility of risk to the ninja involved. When Konohagakure was short-handed in upper-level ninja because of the attack by Otogakure and Sunagakure, the village had to occasionally send genin on higher-ranked missions.
Genin are put in four-man cells or squad, consisting of three genin and a jōnin-sensei, in order to learn teamwork and experience true ninja life under the supervision and protection of an elite shinobi. The make-up of these teams is based on the individual skills of the genin, so that there will be a balance between the teams. For instance, Naruto Uzumaki, who passed with the lowest grades, was put in a team with Sasuke Uchiha and Sakura Haruno, who passed with the highest grades and highest written exam scores, respectively. The teams are usually made up of two boys and one girl.
Due to the fact that genin are the lowest level ninja, they normally provide limited use during dangerous missions (B-rank or higher), and are usually only capable of successfully completing E-rank or D-rank techniques. However, it should be noted that genin is simply a rank, and is not always an accurate representation of a ninja's skill level.
Though genin are relatively low-leveled ninja, they can progress to become a chūnin, by successfully completing the chūnin exams, a set of difficult tasks made to test the skills of genin to see whether or not they should be chūnin.
Chuunin: Chūnin (中忍; Literally meaning "Middle Ninja", Meaning (Viz) "Journeyman Ninja") are ninja who are qualified to watch over and guide other ninja. Chūnin have reached a level of maturity that primarily consists of leadership skills and tactical prowess. This is because the genin who don't have the skills to become chūnin are weeded out in testing. Some of them, like Iruka Umino and Mizuki, function as Academy teachers and others, like Shikamaru Nara, serve as team leaders in charge of small teams who need to make decisions and utilize the skills of the shinobi under their command to the maximum effect. Chūnin are typically sent on C-rank or B-rank missions.
To become a chūnin, a genin participates in a large examination, known as the Chūnin Exams. The only exam seen in the series is a three-stage exam held in Konohagakure. Those who pass the test and become chūnin can wear an identifying flak jacket that holds ninjutsu scrolls. This vest is not mandatory; instead, some opt for more elaborate clothing like capes and robes.
Jounin: Jōnin (上忍, Jōnin; Literally meaning "High Ninja", Meaning (Viz) "Elite Ninja") are generally highly-experienced shinobi with great individual skill who serve as military captains. They are often sent on A-Rank missions, and experienced Jōnin may even be sent on S-rank missions (which are considered to be the greatest difficulty). It is not unusual for Jōnin to go on missions alone. Jōnin are generally able to use at least two types of elemental chakra, some genjutsu, and above-average taijutsu skills.
It is as of yet unknown what one has to undergo to become one. It is mentioned in the Naruto Anime Profiles databook that Jōnin are appointed, however there was mention of a Jōnin exam in the anime's Kurama Clan Arc. When a ninja becomes a Jōnin, they may be assigned three Genin to look over. One part of their duties is to help instruct and train these Genin to become competent ninja. In Konohagakure, it is up to the Jōnin to decide whether a candidate Hokage would be given the position permanently
Shinobigashira: Head Ninja (忍頭, Shinobigashira) is a position in the shinobi system of Kumogakure. It is a rank between the Jōnin and Kage, and unique to its own village. As the highest-ranking shinobi, they are sent on important political missions such as ambassadors for peace treaties with other villages. The only one seen is an unnamed head ninja was sent to Konohagakure to sign a peace treaty nine years ago, and was killed for attempting to kidnap Hinata Hyūga.
Kage: A Kage (影; Literally meaning "Shadow") is the leader of one of the five most powerful Hidden Villages and generally are also the most powerful ninja in their respective villages. They are collectively known as the Five Kage (五影, Gokage). If a Kage has held their position for several decades, as was the case with the Third Hokage, younger ninja are likely to have become stronger than they are. In such cases, the Kage may retire and give the title to someone else; the title, once granted, is held permanently. This creates a case where there are two Kage at the same time, with only one of them actually active, as it was with the Third and Fourth Hokage. After the Fourth died, the Third came out of retirement.
The Kage stand equally with the rulers of their countries, oversee the activities of their villages, and are the leaders of ninja society. They typically are the ones who send the ninja teams out on their missions and make the decisions regarding the safety of the village. The five Kage are:
The Hokage (火影; Literally meaning "Fire Shadow") of Konohagakure.
The Kazekage (風影; Literally meaning "Wind Shadow") of Sunagakure.
The Mizukage (水影; Literally meaning "Water Shadow") of Kirigakure.
The Raikage (雷影; Literally meaning "Lightning Shadow") of Kumogakure.
The Tsuchikage (土影; Literally meaning "Earth Shadow") of Iwagakure.
Missing Ninja: Missing-nin (抜け忍, nukenin; English TV "Rogue Ninja"; Literally meaning "runaway shinobi") are ninja who left their village without the intention of returning, often because they have committed criminal acts or to pursue other personal gains. The ninja village that they are from will often try to track them down and eliminate them. Several missing-nin (such as Zabuza Momochi) do not stop wearing their forehead protector, while others (such as Orochimaru) may discard them. Akatsuki members who do retain their headbands carve long, horizontal scratches across the symbol, to show they have rescinded their allegiances and rejected their villages.
Hunter Nin: Hunter-nin (追い忍, Oinin; English TV "Tracker Ninja") are a special team within Kirigakure's ANBU, given the specific duty of hunting down missing-nin. They could be seen wearing standard armoured ANBU uniform or, in some instances (such as Haku and Ao), a blue kimono with a striped, turtle-necked undershirt. They may also wear a mask with thin slitted eye-hole and a wavy design in place of the mouth, and their village symbol on the forehead. They kill their target, taking the head as proof, and then completely dispose of the body by using various methods, such as cremation or the summoning of wild carrion crows to devour the corpse. This is done in order to make sure the village secrets which a ninja's body holds — such as chakra types, herbs eaten, ninjutsu, special medicine, and kekkei genkai — will not be revealed to outsiders.