Kekkei genkai (Earth-2356)

A kekkei genkai, also known as a bloodline limit, is an anomaly of the DNA of Force-sensitives that allows the wielder to use unique Force techniques. A kekkei genkai's name describes both the anomaly and the resulting technique. Most kekkei genkai are passed down between generations of a Jedi clan, an exception being Hashirama Senju's Wood Release. Likewise, most individuals only inherit one kekkei genkai, but Mei Terumi was known to naturally possess two.

Overview
Generally speaking, there are three types of kekkei genkai:


 * Eye Force techniques are unique eyes with special perceptive abilities, such as X-ray vision or acute attention to detail. Some eye techniques, such as the Byakugan, are present from birth, while others, such as the Sharingan, won't awaken until specific conditions are met. Eye techniques that are consistently inherited within a particular family, such as the Byakugan's Hyuga Clan and the Sharingan's Uchiha Clan, often became synonymous with the clan.
 * Advanced nature transformations combine two basic natures in order to create a new one, such as water and wind to make ice or fire and earth to make lava. Although it was common to use more than one nature, actually combining them requires a kekkei genkai. While some natures were commonly associated with a particular clan, such as ice with the Yuki Clan, others occur within individuals with no known relationship, such as lava being used by natives of Coruscant, Iwa, Kirigak, and Kumo.
 * Certain kekkei genkai grant their users unrivalled ways of using their own bodies. Twin Human brothers Sakon and Ukon could merge their own or the bodies of unrelated people. Kimimaro's Macabre Bone Pulse enabled him to freely manipulate his bones, such as growing an additional spine for him to wield like a whip.

Kekkei genkai madke their users far more powerful than the average Force-sensitive. In times of war they were deadly on the battlefield, and were often deployed to turn the tide of the battle. They were highly effective in this regard, but this went to create issues for them after the conflict was over: survivors of the battle that witnessed or that lost loved ones to kekkei genkai users came to fear and hate them for their actions. They were persecuted because of their abilities, forcing them to the lower rungs of society or driving them into hiding. Even the Jedi Order sect or military body that employed them may stigmatize them, relying on them in combat situations but being unconcerned with their actual survival.

Even though individuals with kekkei genkai were mistreated, the actual kekkei genkai remain coveted by many. Kumo, for example, made different attempts to steal the Byakugan. The Hyuga Clan took steps to preserve the secret of the Byakugan, first by obligating members of its branch families to sacrifice their lives for members of its main family, and furthermore by branding branch members in order to destroy their Byakugan when they die. Despite these safeguards, Ao of Kirigak was able obtain a Byakugan, and he went to great lengths to ensure it could not be taken back.

When attempting to transfer kekkei genkai to others, eye Force techniques were the easiest to work with; the recipient merely needed to be implanted with it. If the recipient did not have a genetic predisposition for the eye technique, using it would demand far more midi-chlorians than is was required for natural users. For nature transformation kekkei genkai, only Hashirama Senju's Wood Release has been shown trying to be recreated in others: Orochimaru attempted to reproduce Wood Release by modifying tests subjects' DNA, succeeding only with Yamato; Kabuto Yakushi perfected grafts of Hashirama that could be implanted in members of the Imperial Sith Acolytes, granting them Wood Release. For bodily kekkei genkai, transferring or reproducing them appears to be prohibitively difficult: to acquire Kimimaro's Macabre Bone Pulse, Orochimaru planned to simply take over Kimimaro's body, a plan he had to abandon when Kimimaro's body was discovered to be dying.

If an individual cannot gain access to a kekkei genkai directly, they can try instead to use it through the kekkei genkai's original user. Sasori could access the Thirkaz's Magnet Release via a sentient puppet made from the the late Jedi Grand Master's body. Orochimaru was the one and only able to use the Impure World Reincarnation to revive the dead.

Source

 * https://naruto.fandom.com/wiki/Kekkei_Genkai.