Onijirushi

Onijirushi is the Kekkei Genkai of the obscure Mazoku Clan. A terrifying ability that is comprised of two major traits, both affected by the special enzymes that exist in Mazoku. The first allows them to passively absorb Natural Energy to create Senjutsu chakra. The second makes direct use of these same enzymes to transform parts of their body in various ways.
== Overview ==
The basis of the Onijirushi kekkei genkai lies in the special enzymes that all members of the Mazoku Clan possess. These enzymes possess an unknown mechanic that allows the Mazoku to passively absorb natural energy, however this is not without its faults. This same mechanic affects their ability to cognitively function, which grows further impaired by the more advanced uses of this kekkei genkai (I.E: A complete transformation). At such a state, a Mazoku would want to do nothing more than kill whatever they set their eyes on.
This becomes even more dangerous when complimented by the second ability that these enzymes give to the Mazoku. By directly exposing parts of the body to these enzymes, Mazoku are capable of transforming their body in a multitude of ways. From being able to turn their forearm into an axe, to something as complicated as protrusions from which their body can fire out pure beams of senjutsu chakra. Given the use of natural energy combined with this, these modifications are brutally efficient and can turn any Mazoku into a killing machine. Doing so further debilitates a Mazoku's cognitive functions however, making them prone to murdering others when even accessing the most basic aspects of their kekkei genkai.
Once they have reached their limit, a Mazoku will naturally reach a point in their mutations where they completely transform. At this point they are stronger, faster, and without the common rationality that would allow for inhibition.
== How to Use ==
Given the unique powers of the Onijirushi, its powers have to be limited within reason of balance. Below are all the details of how exactly this kekkei genkai will be used in the role-play.
=== Mental Health ===
Even when a Mazoku is actively choosing to not use their abilities, they are still under the influence of their kekkei genkai. In order for their ability to be reasonably balanced, and for it to be more realistic to the role-play, part of the wanton need for violence plays directly into a Mazoku's character. No matter who they are, or what their creed may be, someone with the Mazoku kekkei genkai must possess three critical flaws in their personality that can agitate them mentally. E.G., disliking when a person litters, when it rains, when dogs bark loudly, and so on. These critical flaws must be role-played out, and lead to further levels of aggression that could lead to a need to kill whatever they think is agitating them. Even in the case of the second example, the rain itself doesn't need to be the target of aggression, but someone who further aggravates the Mazoku could become a target of their violence.
Each instance where a Mazoku's flaw is aggravated will deduct a ⅒th of their total Willpower (rounded to the nearest whole number if the value has decimals). This can be represented in role-play by the character beginning to suffer from the stress of this exposed flaw. Such as becoming visibly irritable, terse, or violent.
=== Partial Transformation ===
Even when partially transforming, a Mazoku is inadvertantly making further use of the same enzymes that impair their cognitive functions. In order to gather the natural energy needed for their Senjutsu techniques, which for Onijirushi techniques requires half of the original cost, they must sacrifice an equivalent amount of Willpower. This can be further explained in role-play as the character's mental health deteriorating as they begin to make use of their Sage Transformation. The rules of maintaining jutsu still are relevant when using a Sage Transformation technique, meaning that Willpower will still be depleted with the Chakra used in a technique.
=== Complete Transformation ===
A complete transformation will occur when either a Mazoku willingly sacrifices their mental fortitude to go under half of their Willpower's value, or if they reach it naturally through use of Sage Transformation techniques. Upon reaching this state, they are more than willing to kill whatever they feel they want to kill. Even allies are subject to this if they participated in what stressed out the Mazoku in the first place. When a complete transformation occurs, Mazoku enter a unique state. The exact appearance of this transformation, as well as its uses, are an individual occurence. No two Mazoku share the same ability when completely transformed. To help reflect this, the complete transformation of an individual will be regarded as a Jutsu on the wiki. This can either be a named technique or remain without one and simply be titled as "Character's Transformed State". 
While the exact attributes given to these states are individual, there are certain parts that must be maintained throughout all complete transformations. This mainly concerns with how long it will last, and its "rank". Given it is not a true jutsu, the transformation itself does not possess a rank in-character, but will act similarly to what it is most comparable to. This is largely dependent upon the Combat Skills that the character possesses in their Senjutsu (which they must have to make use of their kekkei genkai's techniques). In example, Mazoku A possesses four stars in their Senjutsu. This means their transformed state would have the same cost as an A-Rank jutsu. While it costs no points to enter the state, it will cost half of the points it would take as a jutsu to maintain this heightened form.
Unlike a regular jutsu, a complete transformation cannot be normally deactivated. This is due to the violent nature that comes with the use of this form preventing any sort of discipline that would stop them otherwise. The only way for them to be stopped is if they are incapacitated, by either being forcibly calmed or being incapacitated during a fight. These can be achieved through various methods, the most certain of them either involving genjutsu or actively beating the user into submission.