Demon Fox

Demon Foxes, also known as Spirit Foxes, are a group of Yōkai that reside in the Lost Forest of Yōko that exist a realm of its own. They vary in sizes, with the smallest one being the size of a house cat, and the largest one being able to increase its size to the point where it can easily crush a village the size of Konohagakure under its paws. They are lead by the Senbi no Yōko (千尾の妖狐, Demon Fox of a Thousand Tails), an ancient fox-like creature that is practically a God.

Their strength are usually represented by their number of tails. They are highly intelligent creatures that use what is known as Fox Magic instead of relying on physical prowess. They are capable of feats that are beyond human understanding and possess incredible resistant to elements of this world. It is in their nature to come and go as they please, making them a difficult partner to work with.

Their come in all sizes and colors, but all of them share one similar trait, the ghostly flame that burns on the tip(s) of their tail(s). They are often worshiped as guardians and deities by the people.

Known Demon Foxes
Unnamed Fox Messenger, a tiny fox about the size of a small house cat with a coat of orange fur, and a short bushy tail. It posses the ability to travel freely between the human realm and the realm of Yōko.

Senbi no Yōko (千尾の妖狐, Demon Fox of a Thousand Tails), an ancient fox-like creature that is practically a God. It has a coat of pearl-white fur that shines in the colors of the rainbow, with its tails usually merged into one thick mass that resembles the tail of Shukaku, the Ichibi. It created the realm in which all demon foxes resides in, and feeds on the souls that accidentally wandered into its realm. It is capable of changing its size, possesses clairvoyant, can travel freely between realms, create physical clones of itself by shedding its fur, create life, and even recreate itself from nothing. It is impossible for a human to summon the Senbi.

Fox Magic
Fox Magic (狐妖術, Kitsune Yōjutsu), are spells that can only be performed by the Demon Foxes as they require Demonic Energy (妖気, Yōki) of the Demon Foxes. Fox Magic cannot be copied by the Sharingan. A human can only perform Fox Magic when they are possessed by a Demon Fox. Below is a list of known spells;

Fox Fire (狐火, Kitsunebi), the most common spell used by the Demon Foxes. A ball of blue flames that upon impact will begin burning away the victim's chakra. Unlike natural fire, the Fox Fire does not produce heat, does not cause physical burn, is not effected by water or oxygen, and will continue to burn until the victim runs out of chakra. The more chakra the victim has, the bigger the flames grows. Jinchūriki beware!

Ethereal Form (幽体化, Yūtaika), a spell that enables the user to become ethereal while remaining in the human realm. This not only makes them immune to physical attacks, Ninjutsu, and lets them pass right through barriers and physical objects, but also makes them invisible to the human eye (even to those with Doujutsu). Animals however, can still see them.

Ethereal Hands (幽手, Yūte), a spell that creates semi-invisible arms that have a reach of 2 to 15 meters depending on the skill of the user. The user can also create anywhere from 2 to as many as 50 arms depending on their skill. The arms are snake-like, without any joints, with human-like fingers. They are indestructible, can lift an object of any weight as if it is weightless, and even nimble enough to catch a spinning Shuriken by the hole in its center. Despite being able to lift any object effortlessly, when used to attack or restraint someone physically, each arm only possesses the strength of an average human.

Explosive Curse (爆裂の呪縛, Bakuretsu no Jubaku), a spell that causes anything the user touches to violently explode. The greater the mass, the bigger the explosion. An object affected by the spell with have the letter "爆" (Baku, explode) on its surface. The user has to trigger the explosion by focusing on the object and chanting "Baku", or "Bakuha" to cause all affected objects to explode simultaneously. The characteristic of the object does not affect the explosion. The spell however, cannot be used on living things, as well as the wood created by Mokuton users. Those resurrected by Edo Tensei is considered non-living things.