Shinobi (忍), also interchangeably referred to as ninja (忍者), are the primary focus and the main military power in the series. A female ninja is known as a kunoichi (くノ一). Most come from a hidden village, of which some come from specialised ninja clans, and will perform missions for a fee. These missions can include: doing manual labour, acting as escorts, gathering secret information, retrieving stolen items, carrying out assassinations, etc. In times of war, ninja will come together to defend their villages and land. The clearest characteristic of a shinobi is their ability to manipulate chakra to create and use techniques. Shinobi are expected to be loyal to their villages for life, and any defectors are considered to be missing-nin, and will be marked for death.
Main article: Jutsu Jutsu (術, Literally meaning: skills/techniques) are the mystical arts a ninja will utilise in battle. To use a technique, the ninja will need to use their chakra. To perform a technique, the ninja will bring out and release the two energies of chakra. By forming hand seals, the ninja is able to manifest the desired technique. Because of the extensive number of hand seals and different combinations, there are thousands of potential techniques to be discovered.
Shinobi can use a variety of techniques often based on the utilisation of chakra. This allows shinobi to perform extraordinary feats such as walking on water or walking up trees. Jutsu are separated into three groups, ninjutsu, genjutsu, and taijutsu. Ninjutsu implies performing a supernatural or beyond normal ability, the most common of which is the elemental jutsu. These are created by the user transforming their chakra into a specific nature or 'release'. The chakra types are Lightning, Earth, Fire, Wind, and Water. Other sub-types of chakra natures such as Wood Release and Ice Release also exist, created by combining two of the basic five releases. Taijutsu implies physical body techniques, which may or may not require chakra. Genjutsu manipulates the chakra in an enemy's mind and disrupts their chakra flow. Their senses get fooled which creates illusions, things that the foe believes to be real that are in fact fake.
Shinobi have noticeably more physical capabilities than a normal human being, able to execute feats of strength that would be otherwise impossible for a civilian, even at relatively low levels of skill. For example, their ability to jump. Ninja are capable of leaping many times their own height and permitting them to clear buildings and structures, especially when moving across rooftops or travelling through trees. Even as a boy, Naruto jumped over a fence in the Academy with no significant effort. And near the start of his battle against Sasuke Uchiha at the end of Part I, Naruto jumped from the Hashirama Senju statue to the Madara Uchiha statue, reaching the other end of the entire valley in just one leap. However, moments like these are greatly ignored and overlooked due to the fact that they are so commonplace in the ninja world, even for genin-level shinobi. Ninja also possess strength that far outmatches the average person. A simple kick from Itachi to Sasuke created an exceptionally large crater in the wall. Another time, while Mei Terumī and her team fought against Black Zetsu, they could slash clean through his trees with relative ease and no indication of using chakra to enhance their kunai.
Main article: Ninja Tools
Ninja tools are used as alternatives to techniques. They can include weapons, accessories, and even clothing. Some ninja such as Tenten have mastered the use of such tools, but all ninja are able to use the most common to some degree. A standard shinobi will have a pouch equipped with many tools, and nearly every ninja is equipped with at least a shuriken holster. Most also possess and wear a forehead protector with the symbol of the village they derive from, though the ninja does not necessarily have to wear it over their forehead. The Inuzuka clan's ninken and Aburame clan's insects are also classified as tools.
- The word "shinobi" and "endure" both have the same kanji character.