Nenmu

Nenmu (撚夢, Twisted Dreams) is a unique power of the Kurama Clan. Very rare even within the clan, it allows the user to cast very powerful genjutsu, illusions that can be used to trick the brain and kill the target without ever landing a single blow. This causes the inheritors of this kekkei genkai to become formidable genjutsu users, such as in the case with Asuna Kurama and Chinka.

Description
The strength of illusions can be severely undermined. By controlling the internal system of a shinobi, a battle can be ended before it even begins. Even the most fearsome of opponents could be felled before their grand prowess is even exerted. Mental combat comes before and within physical battle, and it can be the deciding factor in what is to come out of confrontation. Assassinations, puppetry of individuals, infliction of sickness and more, all without the use of a single ninjutsu. Genjutsu is a powerful tool and this Kekkei genkai serves to amplify it to the utmost degree.

Such jaw-dropping power is not without its drawbacks. This power seems to have a mind of its own, awakening a darker side of the shinobi to utilize the power for destruction. This often overpowers the user and causes them to become a danger to everyone around them. However in a few cases, the user has managed to reverse fate and achieve dominance or even cooperation over their dark side. This allows them to harness this extreme power to the fullest extent, and even exert a physical transformation at will. Only a handful have reached this stage of the kekkei genkai and can only be fought by genjutsu users of equal prowess.

Trivia

 * Thanks to Ash for the translation.
 * A named variation of the Kurama Clan's Kekkei Genkai for Kami and Chix's use.