Chakra
Chakra itself originated from a Tree, a fruit to be exact, plucked and eaten(I suppose), and since then people have been capable of connecting their physical and spiritual energies to form Chakra. Since the release of Chakra, it have become a sort of Life Energy, which we produce naturally but slowly. Essentially, should you run out of chakra, you die.
The chakra is spread out, into a system similiar to our blood veins, but known as the Chakra Path System. We got pressure points located around our body, which is where we release our chakra through.
There are a select few Pressure Points, which are like blockers, which keeps us from ultilizing our Chakra fully, known as the Eight Inner Gates. Removing the limiters, we allow ourselves to release even more chakra at once.
We ultilize Chakra to do feats we normally wouldn't be able to, such as creating Tree/water walking.
There a many a kind of Chakra. It have been mentioned at several times that each person also radiate a different kind of chakra, which allows sensors to define them from eachother. Natural Energy to form Senjutsu is not exactly chakra, but an impure form which allows for the mix of Phsyical, spiritual and Natural Energy to mix to create a stronger force.
Bijuu Chakra in itself, also increases the user's chakra capicity in itself, along with their overall strength and endurance.
Shape Manipulation
Shape Manipulation is a way we mold our released chakra differently. We used it to specifiy a shape, such as a cube. We use it to specify increase in size or decrease. We can make our Cube dense, or rotate hazardous. Our prime example is the Rasengan, which was manipulated densely together while rotating widly. Loosing the the compression it would simply erupt in an outward explosion.
Shape Manipulation is also the pre-training for Nature Transformation.
Nature Transformation
Nature Transformation, simply put - Is an advanced form of Chakra manipulation, which allows us to go further into it's mechanism and define our chakra's innate charatertics and overall properties. Combined with Shape Manipulation, we could e.g exhale a stream of fiery fire.
Naturally, all Ninjas have an inherient speciality which can be discovered with these cool paper tags we got. But in our RP, it matters little, as all can learn all, and the only thing about having a speciality in this area, allows us to perform it with but a single hand sign should it contain any.
Furtherly put, theres the ability to mix two chakra natures at once creating an entirely new element, being special from the remaining, basic five elements being Fire, Wind, Earth, Water and Lightning.
Ninjutsu
I believe we have three different basic types of techniques to do use. These are Taijutsu, Genjutsu and Ninjutsu, whereas Ninjutsu is one of the three. Ninjutsu is one of the basic molding and manipulation of chakra as described above. Often techniques are associated with handseals to make the flow better in order to perform certain techniques. However there do also exist certain non-handseal techniques, such as our prime example; Rasengan.
Within the category of Ninjutsu, there are several sub-categories which are used quite differently than regularly. This could be Medical Ninjutsu, Sealing Techniques which are often associated with tags, however still pertain Ninjutsu, Space-time summoning animals, etc.
Taijutsu
One of the three Basics. Taijutsu also known as body techniques, are the fastest executable actions capable. It is both quicker than Genjutsu and Ninjutsu. It requires no handseals and at most, it requires a stance at some cases. It's ultilized through our stamina, also known as physical energy, and can oft be combined with Ninjutsu for higher lethality. This falls into sub-category known as Nintaijutsu.
Specialist is this area, mostly seek to achieve the ability to unlock their few selected Tenketsu, also known as the EIGs, which removes their limiter, allowing their body to exceed normal limitation and increasing their overall raw prowess.
One could say this falls under the category of Yang, considering the physical usage.
Genjutsu
Genjutsu is the last of the three basics. Genjutsu is also known as illusionary techniques. As the name suggests, it applies illusionary effects to the target. Put simply, the caster takes control of the chakra flow within the target's brain in order to make changes to the five senses, thus creating an illusion of their choice.
It's more seldomly seen used, as most prefer the actual tangible, physical effects, that Ninjutsu and Taijutsu posess.
Usually while under the influence of an illusion the victim appears immobile, and in some cases they may still be mobile, moving around in the illusion itself.
There are a variety of ways to break a Genjutsu, such as creating actual physical pain to bring back to the victim to reality. A sort of override of the chakra system, being injected with foreign chakra in order to flush out the illusion. A spike of chakra to 'reset' it to it's normal state.
It was also shown that through strong smells with chili pepper bombs, that one was capable of breaking an illusion, but I don't think that's viable in our RP.
It's said that this category falls under Yin-Release.
Yang Nature
Yang, which I view as Physical Energy, is also known as the energy which is accounted for as vitality, our life energy. Self-empowerment, longevity. This is what I see when I look at Yang release. It's what breaths life into objects. It had a vitalizing effect on Mokuton, which caused an outburst of growth.
It's said Akamichi's Multi-size techniques falls under Yang-release.
Aside from this, Yang Nature can be combined with Yin-Release to ultilize a combination of them both.
Yin Nature
Yin Nature is also known as the spiritual energy. It's said to create form out of nothingness, alas it's the ability that rules imagination. Mentioned by the Second Mizukage was that Genjutsu itself falls under the category of Yin-Release, as I mentioned earlier, and such as Tayuya's usage of her Dokis, which proved to contain much more spiritual energy than physical.
Aside from this, Yin Nature can be combined with Yang-Release to ultilize a combination of them both