Busoshoku: Bugutai

Busoshoku: Bugutai (武装色 武具体, Busō-shoku: Bugutai; literally "Color of Armaments: Armor Body") is said to be the highest level of reinforcement. It combines the principles of imbuing oneself within and outside of their body, compressing the entirety of one's Haki into a powerful armor that both enhances their defensive capabilities while explosively enhancing combat prowess.

Overview
It is also referred to as Buso Bugu (武装 武具, "Armament Armor"). Busoshoku Haki is a power of the body, something that turns one's own willpower into a means for direct combat to serve both offensive and defensive purposes. In other words, the user's life energy becomes an extension of their physical body, allowing them to perform all sorts of feats that would normally be considered difficult or impossible otherwise. When a user is able to fully master their Busoshoku Haki, it becomes possible for them to channel its utmost potential at once, adorning their bodies in a powerful armor that serves as a second skin.

However, the true power of the Armor Body does not come from its use as a defense; after all, one would think simply putting on an armor of Haki would be superfluous when methods of simply hardening one's own physical skin are available. Kurama, when teaching the skill, mentions that although the technique is named for its appearance, calling it merely an armor is a misnomer. It would be more accurate to say that this is a technique of turning the soul into a sort of complete "exoskeleton" that is controlled by one's will. The entirety of one's body is encased, almost as if what was once a body that contained the soul, is now a body being contained by its very soul. By doing such a thing, one's body that is clad in the armor no longer requires movement with the physical body, but is simply "willed" to move by the user themselves. Because of this, the user's movements are no longer restricted by physical limitations; they can achieve heights of strength, speed, agility, and so on, that far exceeds what their physical body would normally be capable of performing.

As the armor itself is created and behaves based solely on the user's willpower, the heights of strength, speed, and durability, among other things, are virtually limitless; proportional only to the user's experience, skill, and ultimately, their strength of will. Similarly, unlike the generic appearance of the hardening form of Busoshoku, the armor body takes on a shape, form, and coloration based upon the user's own soul. While some characteristics can be manually altered through enough experience with the armor, it serves as a reflection of one's own self: their aspirations, their personality, and also, their flaws and fears. Some armors may appear robotic in nature, while others can look like warrior armor such as those worn by Samurai or Knights; though even that much does not cover all the possibilities for how the Buso Bugu can manifest. For every user, the armor is different, just as each person themselves are different.

Kurama mentions this technique was originally meant for the purpose of creating a Utopian world. It would be a means for crippled individuals, ones that have lost their limbs, to be able to move as though their bodies were without injury. Those who have frail constitutions, or suffer from physical diseases, would also be able to live their lives freely without concern of those limitations.

Behind the Scenes
While this concept was inspired by multiple sources, the concept of how the armor's appearance and characteristics are shaped was based on how Duel Avatars are created in the light novel series, Accel World.