Rieka is the rawest form of life itself. Reality, all events that occur, and the smallest to largest creature are all kept in existence by rieka.
Trained individuals can utilize their internal rieka to perform a range of feats from firing energy projectiles to altering the senses themselves. In essence, there is no limit to what someone can perform with rieka by manipulating it, if they have the required power, since it is everything and anything that could possibly be. For example, the creation of Eternia, an entire realm seperate from Valmasia was put into place, by the sole influence of one being.
Role in Eternia
Unlike Valmasia, Eternia is not only a realm of rieka, but physical energy as well. The majority of Eternia creatures are composed of about 80% physical matter and 20% rieka, because of this, their capabilities with rieka is much more constrained compared to the spiritual entites of Valmasia.
The 'soul' is however composed of entirely rieka, thus why physical creatures still require a portion of rieka within their body, because without it, the body would be completely hollow and impossible to exist in reality.
Creatures of Eternia are also a much more 'tastier' source of food for the Jinn, which is why they go to such extremes to escape the rift and feast on the emotions of Eternia-based creatures. This is most likely due to the physical body that Eternians possess, which spurs much more emotion in contrast to spiritual creatures.
Rieka Types and Capacity
The rieka of every creature is unique, some are born with a large amount, whilst others are limited. All creatures have a different rieka capacity, basically an estimation of their limits, this however can change with practice.
Rieka traits can also be inherited from parents, or a specific bloodline trait, for example a Drakanite will naturally be adept in elemental fire rieka, because of their rieka design.
There are several types of rieka, the main types include-
Internal: Rieka that is drawn from the users body, their own natural energy. Every creature has a base rieka that they can manipulate, allowing them to perform a range of tasks. The majority of techniques are affected by the users internal rieka, it is a indication of their power with rieka-based attacks.
External: Rieka from outside sources of the the user, anything that is outside of the users body. For example, if someone was to extract the life from a plant, it would be considered an external technique because the performer is utilize a rieka other than his own.
Elemental: A mixture of both internal and external rieka. The user draws on one or more of the five elements - water, fire, earth, wind - and mixes the unique rieka with his own to replicate the element under his will.