This is an analysis and brief history behind the Kyuubi Kitsune and the Martial Art Kyuubiken.
Kyuubiken is the military martial art of the Ki Fox tribe that has been around in variations for over 3000 years. It originated as a form of meditation and has strong ties with Earth Magic. there are many Kyuubi Kitsune beings that help control and balance Nature.
Long ago, a powerful Multi Tailed Kitsune Fox Deity named Kitsune Kami, appeared to the early nomads. He had the appearance of a feral fox with multiple tails. Each tail contained a different power. He had 9 in total, but had the ability to produce up to 16 if needed. He showed the fox nomads how to meditate and harness their Ki or life force. With that, the Early fox people were able to accomplish many great things for centuries.
Over time, they applied it to the combat arts. Thus the beginning of Kyuubiken, which translates into Nine Tailed Fist, was born. The basics of this art has similarities to Chinese Kung Fu and elements of Korean Taekwondo. Its spiritual Aura and Ki elements are base loosely on the Hadou philosophy from the Street Fighter series. The focus of Kyuubiken is to maintain harmonic balance of mind, body and spirit. It originated from the power shown to the fox nomads by the Kitsune by means of the magic from His 9th tail. The Nomads learned to harness that power and its Passive Magic within themselves through intense meditation. It was then focused and combined with the physical elements.
There are 4 elements to Kyuubiken. 1) Physical- the actual combative element to the martial art. 2) Mental- which pertains to focus and Clarity of the Mind. 3) Ki control- now this has nothing to do with Dragon Ball Z or Naruto. Every living thing has a life force and that life force can be harnessed through special training. With enough skill, your own ki can be used to enhance and protect your physical attributes( similar to Armorment Haki from One Piece). But overuse of this can be very taxing on the body. Now the final element, is 4) Spiritual- This is the Ability to Sense and Manipulate Aura Which is done through meditation and training the 5 senses. Depending on the type of individual and the will of the user, it'll also determine the kind of ki flow that is used. The Yin and Yang if you will. The darker your spirit becomes due to aggression or greed, the harsher your ki will be and it came prove detrimental to your physical being. this has caused Felix to transform into the Demon Kitsune form ( just like the Satsui no Hadou from Street Fighter).
With proper Mastery of these elements, the user can drastically increase their strength according to their level of output. But this is only possible if the user has a strong enough passion since it is directly linked with the strength of their spirit. when focusing the life force, Ki can often become Visible. And since it is linked with The kitsune's magic elements, it can at times produce an illusion of the user possessing 9 tails.(Felix one the other hand, who is essential merged with the Kitsune, will manifests 9 PHYSICAL tails instead of illusions)
Kyuubiken has since become the official combat art of the Ki Fox tribe military and is often passed down to the children for self-defense. Not many individuals possess strong enough Ki control, as it requires a large amount of time and a decent amount of personal spiritual awareness in order to access it. This is not a form of magic in itself but is based on the basic living magic as shown to the Nomads by the Kitsune centuries ago.
Felix Floetry, was trained in Kyuubiken by his late Father sometime before the invasion and conquering of his Village years ago. His father rescued him from the Mercenary leader was murdered in front of Felix in the process. before his rescue, Felix was gravely injured by his captors. in order to help heal Felix, his father used a powerful Kitsune Stone that housed the ancient fox Spirit. By using a special Spirit binding spell he learned from Gifoxes, Striker (Felix's Dad) merged the Complete essence of the Kitsune Deity with his son's spirit. It made them one in the same an turned Felix into a Demigod. over time, Felix has mastered both the Physical and Mental elements of the Martial Art style and has become adept at Ki control and Aura Manipulation. he still hasn't mastered the Full potential of the Kyuubi Kitsune though, as frequently depleting his Ki can severely tire him out and losing focus on his mental control can make him go into a temporary aggressive feral state.
Kyuubiken practitioners can go toe to toe with magic users as long as the magic user's power doesn't vastly out match their own. Felix likes to use his martial arts skills as a last resort because he absolutely abhors violence. His past experiences had made him rather timid at times but he will use it if his well-being or those of his friends or loved ones are in eminent danger. He has since gotten over his timidness
this has been a brief history and assessment of the nine-tailed fist martial art as well as an explanation about how Felix became a Kyuubi Kitsune