±± Ninja ±±
A ninja is someone who uses their full abilities in the service of his/hers beliefs, working to achieve a goal. This goal can be anything from peace to war, money, destruction, personal griefs or even revenge and can be shared with others or individual. Most ninjas are fighters and correspond to the bulk of the military force of the great nations. However, a ninja doesn't need to be a fighter. Even medics or a simple carpenter may, in times of need, use his abilities (medical knowledge or abilities in working with wood for example) to accomplish the goals he set to himself, following his beliefs.
±± Chakra ±±
Chakra is the energy that is formed through the passive combination of both the Physical and the Spiritual energies in a sentient being (every living being with a conscious mind has chakra). Physical energy corresponds to the vitality of the body and its own energy. Spiritual energy corresponds to the mind or spirit, and comes from the awareness and "soul" of each sentient being.
Some ninjas have high levels of chakra because they have great physical energy (like the Akimichi or even Tsunade) and others because of their spiritual energy (like the Uchiha and the Yamanaka). However, its much more difficult to increase the spiritual energy than the physical one, thus why all ninjas pass through intensive physical workout.
Yin and Yang are based on this same concept. Yin is the basis of the spirit while Yang the basis of the body. In this i won't go into more dept because there are 2 things to consider: Yin/Yang manipulation in our RP is different from the manga one and both are more or less inacessible.
Chakra flows in a circulatory system inside your body, in a way that much resembles the blood circulation. This circulatory system has 8 small reservoirs that act as both storage but also chakra regulation. These are the eight inner gates. Along your circulatory system, small "portals" exist that enable you to expell chakra from your body. These are called Tenketsu and there are 361 of them scattered allong the body. When a tenketsu opens, chakra poors out of it. Its by molding the chakra that comes out of the tenketsu that you produce ninjutsu and genjutsu.
±± Ninjutsu ±±
Ninjutsu, or Ninja Arts, is the ability to, through the use of chakra, accomplish tasks that would be otherwise impossible to do. Ninjutsu are done by 2 stepts: focusing your chakra and molding your chakra. Focusing is using your will power to "will" a portion of your chakra to do something. On the other hand, molding is giving your chakra a set of characteristics that will enable you to produce the desired end effect.
Think of the chakra flow as our breathing. Normally, it happens passively, without any conscious intervention. However, when you need to you can use your will to control it. Its the same with your chakra flow. Its happens normally without your consicious intervention. However, you can focus your chakra and make it produce something.
Now, molding the chakra is done by two basic principles: Shape Manipulation and Nature Transformation. These correspond to the two broad areas that one needs to change in the chakra to produce a jutsu. Shape manipulation pertains to the ability to give your chakra a desired form while Nature transformation pertains to the ability to give your chakra a desired set of characteristics/properties. Sometimes, to better mold chakra, ninja use Handseals. Handseals are simply hand gestures that allow the ninja to more easily concentrate and mold the chakra into the desired technique is