Shamanism

In the context of real life, "shamanism" is a spiritual/religious type of belief in which powerful spirits inhabit the features of nature. These spirits can be kind or cruel to humans, but in either case, are treated with the utmost respect while in nature. In addition, some shamanist beliefs place animals in high regard as spirits.

Examples - Or near-examples - Of shamanism include many tropical island cultures, Native American beliefs, and Japanese shinto practices. Sadly, in many places where shamanism was once widely practiced and people lived in harmony with nature, the encroachment of Christian explorers has warped perception of these beliefs and perhaps irreversibly damaged the rich mythology and rituals associated with them.

Within the Universe of BZPower Battles, shamanism is a bit different. Shamans are those with the rare capacity to see and interact with spirits that would normally be outside the scope of mortal perception. However, this alone does not define a shaman - The traits that determine a shaman's qualities are the ability to truly understand spirits, and to find harmony with them.

Uses of shamanism are varied - Divination, blessings, curses, protection, and even combat. While shamans could, in theory, use any spirits in combat, for any kind of true effectiveness, they must use a Spirit Ally that holds a special connection with them. Combat shamans must use a medium of some kind so that their spirit can interact with the physical world.

From what has been said, it seems that shamans were once persecuted, and thus prefer to stay low...However, this mistreatment has not been explained in depth.

Ghost-Type
One of the most common, Ghost-Types are the spirits of dead individuals - Usually warriors. They often form a contract with their own families or those whom they are attached to, acting as Spirit Allies for future generations. While they can be a bit weak, they have incredible growth potential. Perhaps their greatest strength and greatest weakness is their "identity", which makes them so versatile and able to improve - They can be loyal to a fault, or terrible backbiters; overly compassionate, or coldly merciless. They also are often afflicted with greed for worldly possessions and a desire for vengeance in some way, forging chains of weakness that are hard to break.

Beast-Type
Generally the spirits of animals that have attained some form of "enlightenment", these spirits will most often ally with those who show them true kindness. They are common like Ghost-Types, and often on about the same level of actual strength, but usually have certain advantages due to their animal traits that put them ahead of Ghost-Types. While roughly the same intelligence as a human, they still have an animal's strong instincts and caution - They are very hard to control, and their trust is not easily earned. Just like training a normal animal, though, if the shaman keeps working at it, they'll find that Beast spirits are unwaveringly loyal to those who prove themselves trustworthy and caring.

Familiar-Type
Unique in that they have their origins in mortal craft, Familiar-Types are most often the centrally weakest type and rarely ever effective alone. Thus, their main advantage is very important: Due to being made by mortal magic, given enough time, energy, and the proper materials, any number of these spirits can be made. They're typically small and simple, although many are larger and more elaborate. Another double-edged sword to them is their generally low intelligence; in most cases, they're easy to control, but cannot think for themselves. However, it must be remembered that the traits of weakness and low intelligence do not apply to all Familiars; a small number outstrip even Elementals in strength and intelligence.

Elemental-Type
The rarest of the average Spirit Types, Elementals are named because they are strongly affiliated with an element of nature - From fire or lightning to wood or sound. The disadvantage to them is that they are very proud and wary of humans; even if they can be convinced to ally with a human despite their ego, it can still be incredibly difficult to gain their trust and control them at that. However, once the shaman manages to earn this type of spirit's respect and loyalty, Elemental-Types are mighty as - Excuse the pun - A force of nature. Elementals are incredibly wise and experienced, and the oldest of them are actually easier to befriend and bond with; it is, however, their raw power that makes the elders hard to control.

Nature Spirit
Not to be confused with Elementals, which are manifestations of an element, Nature Spirits are the representations of features in nature - i.e., a mountain, or a river, or a field of flowers. These are believed to have been among the very first spirits to commune with shamans, and are often kinder to humans than the Elementals they are related to. As a note, like Elementals and Familiars, Nature Spirits are rarely ever connected at all to a deceased creature; also, many are quite potent healers.

Avatar
Among the most powerful of spirits, Avatars are representations of gods and other deities on the plane of mortal existence. Exceedingly fickle about when and where they help out, nigh but impossible to fully understand, incredibly proud of their powers, and all in all very temperamental, calling an Avatar a handful would be a gross understatement. While not quite as difficult to bond with as the majority of Elementals, many Beasts, and some Ghosts, the patron deity's influence often stirs problems.

Shugojin-Class
The basic level of spiritual power. Meaning "guardian spirit", they usually cannot form an effective combat form at this stage, and act best as bodyguards unless they manage to ascend to Seirei-Class. This is the most common spiritual strength to be seen. The problem with these spirits is that they often still possess the negative qualities born from either living as a mortal or shunning mortals; stubbornness, uncalled-for wariness of others, coveting physical possessions, etc., etc. Spirits cannot grow unless they can shed this kind of attachment to the living world, while keeping such positive bonds as love for their family.

Seirei-Class
Intermediate in terms of a spirit's power, the term means "holy spirit". While the spirit is attached to a shaman, Seirei-Class strength must be attained by rigorous physical training, intense meditation, and most importantly, a strong bond and understanding between shaman and spirit. As well, however, a Ghost-Type or Beast-Type spirit that has existed for around 500 to 2,000 years, reached a higher level of enlightenment, and/or learned to let go of their worries and other negative bonds to the living world can quickly reach a stronger level of Seirei-Class power. Most notable shamans have attained at least this level.

Kami-Class
A level where a spirit is at its peak of strength; meaning "deity". This can only be attained by a certain training which is kept a secret from most shamans, as most who go into the training die before making any progress. These spirits are incredibly rare, and cannot be subjugated by force and threats - Each spirit has different expectations for a shaman to control it, and while they rarely harbor pride or arrogance, they will never lend more power than is needed, and will only cooperate when the situation calls for them. Not much is known of this level, but only a very small number of shamans have attained it.

Invocation
Known by many terms besides, an invocation is simply the act of summoning a spirit fully. This is usually done so that the shaman may commune with them, or to prepare for the use of a medium.

Medium
Integral to the complete channeling of a spirit into the mortal world, the medium is a physical object that the spirit will enter as a body and alter as it sees fit. This allows them to interact with regular mortals and the physical world at large.

Reiryoku
Meaning "Spiritual Power" in Japanese, this is literally the power of a being's spirit and soul. Also known by names like reiatsu, which is used by the Shinigami and Hollows in particular, reiatsu is the usual energy used to track a creature by spiritually-aware beings, and is often used to place a rough numerical amount to an individual's core level of power.

Furyoku
Means "Shamanic Power" in Japanese. Used by shamans primarily to form OverSouls, cast their spells, etc., etc., furyoku is known by many names and vital to many techniques; from ninjutsu to sorcerous spells. Many ninja know it as "chakra" or "chi", while the vast majority of spellcasters know furyoku as the two separate energies of "mana" and, in some cases, "prana"; while furyoku can come from many sources, in other forms of terminology, mana comes from outside sources, and prana is generated inside of the body by breathing and physical activity. Both are essentially identical, but the way the energy is generated defines how those terms are used when not using the umbrella term furyoku.

Spirit Ally
While shamans are able of seeing, interacting with, and - To a degree - Harmonizing with all spirits of a level within their possible range, it is considered essential for a full-fledged shaman to choose their Spirit Ally. This is typically the spirit that is closer to their heart than normal, and that they deeply care for. However, there are an unfortunately large number of shamans who force spirits to follow them unwillingly.

Technically, it is possible to possess multiple Spirit Allies - However, this is impossible for an average shaman, and difficult for even many higher-level shamans. Their are multiple reasons for this - Spirits competing for attention; the time and energy required to forge true bonds with one spirit, let alone any more than that; and the strain on the shaman's soul, just to name the three predominant challenges.

Hitodama
In a technique to compress the spirit's energies into a more manageable form, the shaman draws their spirit into a tight sphere around their "soul", creating the imitation of a hitodama or will-o'-the-wisp - Namely, a colored ball of flame or mist, with a stylized version of the spirit's face on the front. This makes the spirit much more capable of following their master without giving readable cues to spiritually aware foes as to their abilities, and more convenient for rapidly forming an OverSoul.

Possession
One of the methods of invocation, possession is where the shaman "invites" a spirit into their body. The most common Possession technique is Seigyo o Hōki, "Relinquished Control" - Where the shaman lets the spirit gain complete control of their body for a predetermined length of time. However, there is also a rarer, but much more effective technique known as Kyōdō Sagyō - "Joint Operation" - Where the shaman and spirit control the body in unison. The difference in useage because, while the first depends on the unity of spirits, the latter requires harmony between souls. Synchronizing two spirits simply requires skill and precision - However, synchronizing two souls requires unwavering bonds of loyalty and care between the spirit and the shaman.

OverSoul
An OverSoul, abbreviated "O.S.", is an advanced channeling of the Spirit Ally. They come in three dominate types - Spirit-Type, Weapon-Type, and Armor-Type. A Spirit-Type is an entirely separate entity; a Weapon-Type is a weaponized form of the Spirit Ally's "body"; and an Armor-Type, the most mysterious, is so far only known as the Spirit Ally's so-called body shaped into some manner of armor. Forming an OverSoul requires a medium that has special meaning to both the shaman and the Spirit Ally, as well as an above-average level of harmony between the two souls.

Trivia

 * Shamanism seems to share some relations as a technique with the Dying Will Flames and the occasionally-mentioned "Nen", in that all three somehow connect to life or the spirit.