Olfactory Genjutsu

Scent based illusion techniques remain among the rarest forms of yin release used to initiate genjutsu attacks on opponents. Though unusual they are highly effective methods of delivery often used as supplemental tactics in Kyrgyzishi Clan attack patterns. The versatility of this style of attack lends itself well to many different combat strategies. As the Uchiha were the primary impetus for the creation of this style of genjutsu it remains particularly effective against members of this clan, as well as many other types of dōjutsu users.

History
The Kyrgyzishi developed this style of genjutsu after their initial defeat at the Uchiha's hands during the Ten Fingers of Blood Stained Hands massacre and their subsequent dealings with Hidden Mist. These techniques were developed to mimic both the Hiding in Mist Technique and Clam based genjutsu that worked so well against the Kaguya Clan as a counter to the Sharingan in future conflicts. Shodaime Oyabun's experiments with weaponized Baku and Ōnyūdō pheromones led to the creation of various aerosolized delivery methods.

Usage
The user releases a fragrant or malodorous gas, mist, fog, aerosolized chemical, particulate, or other substance into the immediate environment. Any target with functioning olfactory receptors who inhales the odorants emanating from the attacking substance finds the user's yin chakra invading vulnerable cerebral structures. The target's sense of smell becomes the pathway for delivery of the invasive chakra and initiation of genjutsu. Without intervention susceptible subjects fall under the user's genjutsu.

Advantages
Olfactory Genjutsu has several advantages over other types of delivery methods:
 * Capable of continuously attacking multiple targets, similar to sound based genjutsu.
 * The Genjutsu can be continuously applied as long as the substance remains ambient in a certain location. Targets who break out of the genjutsu can find themselves pulled right back in without an effective counter.
 * It is particularly effective against targets with enhanced olfactory reception, such as those in the Inuzuka Clan. As such, these techniques are often used to elude trackers of this type.
 * Most delivery methods in this category facilitate camoflauge tactics, similar to those used by shinobi from the Hidden Mist.
 * Can be delivered in a time release fashion so that genjutsu only initiates upon saturation of the targets respiratory system or on remote trigger from the user.

Risks
Genjutsu delivered through the sense of smell has notable weaknesses:
 * Since it is designed to be detected, it will initially tend to give away the user's location to a target with at least Kakashi's level of scent tracking ability similar to sound based genjutsu. This can be alleviated to a large degree by remotely triggered odor sources or immediate relocation. However, that requires some amount of preparation which may not always be opportune. This is only a problem if the user wishes to remain hidden in the first place.


 * Odor based genjutsu is as susceptible as sound based genjutsu to interference from wind based counterattacks. Again this weakness can be somewhat mitigated by large AoE coverage so that vacuum from the wake of wind gusts drags in as many odorants as are repelled. Thus eliminating most kinds of wind based counters. However, this is a particularly chakra intensive solution.


 * Targets without functional olfactory receptors or those without vulnerable cerebral structures, such as Aburame insects, remain immune to the effects of these delivery methods.

Categories
Olfactory Genjutsu can be divided into three main categories, which generate a variety of effects:

Mind Pollution

 * Manipulate emotional disposition in order to traumatically influence the subject's mind state gradually over an extended period.
 * Torture subjects into a state of mental anguish and distress, resulting in depleted mental resilience. Thus allowing for swift effective interrogation.

Demonic Illusions

 * Trigger sensory overload, assail subjects with unbearable bodily sensations and bewildering visions.
 * Induce hallucinations, whether subtle or extravagant, in order to distract, misdirect, or disrupt an opponents reaction to events.

Binding Illusions

 * Restrain subjects by internal obstruction of motor control.
 * Render subjects catatonic within a deteriorating vegetative state.

Mind Pollution: Aggravated Breach of Trust

 * Kanji - 精神公害・ 特別背任
 * Rōmaji - Seishin Kōgai: Tokubetsuhainin
 * Rank - A-rank
 * Range - Medium
 * Targets - Multiple
 * Class - Combat Genjutsu
 * Usage - The operator releases a colorless mildly fragrant perfume from multiple sources over a 50 meter square area. Saturation takes place over a long period of time. The chakra levels within the perfume remain uniformly low and can only be detected by advanced sensors, like Karin, and Hyūga's, such as Hinata and Neji.
 * Effects - subjects experience gradually increasing paranoid delusions of confusion, fear, and aggression. causing them to become ever more suspicious of and eventually attack their teammates.

Mind Pollution: Dogmatic Phantasm

 * Kanji - 精神公害・ 独断幻夢
 * Rōmaji - Seishin Kōgai: Dokudan Genmu
 * Rank - S-rank
 * Range - Close
 * Targets - Singular
 * Class - Interrogation Genjutsu
 * Usage - The target is bound by physical restraints or a restriction seal (such as that used by Danzou on Sasuke). Interrogators then release a pleasantly fragrant perfume into the holding cell for a period of time.
 * Effects - Upon saturation the target is assaulted with visions of his worse fears. This ongoing onslaught saps the subject's will within a matter of minutes, hours, or in rare cases, days. The subject then becomes weak and subdued. Having no defenses left, the target will begin to reflect mentally on any questions asked. These mental reflections render as imagery within the minds of the interrogator and subject, allowing information to be gleaned at will.

Demonic Illusion: Phantasmagoric Miasma

 * Kanji - 魔幻・ 変幻自在瘴気
 * Rōmaji - Magen: Hengenjizai Shōki
 * Rank - S-rank
 * Range - Medium
 * Targets - Multiple
 * Class - Supplementary Combat Genjutsu
 * Usage - The user generates an initially odorless opaque gas, resembling a smoky fog, to permeate a particular area. A region of about 50 meters in diameter becomes quickly shrouded in foggy darkness produced by the miasma. Saturation of the gas is reached within the first minute and the user's chakra fully invades the target's system. However, the genjutsu does not take effect immediately. The user remotely triggers the genjutsu whereupon a nauseating miasma penetrates the targets nostrils. Target becomes intermittently distracted as an attack opening.
 * Effects - The environment and user become totally obscured. Subjects experience visual hallucinations of unavoidably hostile, spectral assailants. The target experiences agonizing pain from the ghostly attacks. Meanwhile the user freely and randomly times attacks to deal severe damage in unison with the apparitions.

Demonic Illusion: Abnormal Underarm Odor

 * Kanji - 魔幻・ 腋臭
 * Rōmaji - Magen: Wakiga
 * Rank - A-rank
 * Range - Close
 * Targets - Singular
 * Class - Supplementary Combat Genjutsu
 * Usage - An invisible, diffuse, foul smelling aerosol emanates from evaporating sweat leaking off the user's underarms, while engaged in close quarter combat.
 * Effects - Odorants distort the target's sensory input creating an inaccurate  representation of events. This degrades the target's ability to block or evade incoming attacks due to offset perceptions of velocity, position, and AoE. While this is not a binding genjutsu it also effects the target's motor functions, hampering precision movements and causing the subject to become cumbersome as if in a state of intoxication. The effect is momentary and can only be detected at the time of activation. As high speed combat takes place during these periods, detection by anyone other than an extremely skilled sensor of some kind is highly unlikely. Unless the subject exhibits vast experience or incredible intelligence risk of deduction also remains minimal.

Binding Illusion: Neuromuscular Havoc

 * Kanji - 金縛り幻像・ 神経筋大混乱
 * Rōmaji - Kanashibari Genzō: Shinkeikin Daikonran
 * Rank - S-rank
 * Range - Medium
 * Targets - Multiple
 * Class - Combat Genjutsu
 * Usage - The user releases an ionized, translucent, acrid smoke, which quickly diffuses, rendering a thick haze over an area of 40 meters in diameter. The sharp, pungent stench immediately invades the target's consciousness, initiating the genjutsu.
 * Effects - Upon saturation the targets fall under a neuronal feedback loop causing them to experience virtual rewiring of their neurophysiology so that central nervous system randomly diverts motor signals leaving the brain into the body's sensory receptors. Those signals travel back to the brain and become amplified. The user registers these amplified signals as excruciating random sensations, causing spontaneous, involuntary, motor reactions which in turn trigger further agony. All outward movements cease as subject remains trapped within the debilitating indefinite feedback loop. Death may even result as the amplified signals eventually induce neurogenic shock on the system over a prolonged period of attack. The victim experiences hypothermia, fluid depletion, tachycardic arrhythmia, weak/rapid pulse rate, low blood pressure, and ultimately death.

Binding Illusion: Total Paralysis via Halitosis

 * Kanji - 金縛り幻像・ 全身不随経由口臭
 * Rōmaji - Kanashibari Genzō: Zenshinfuzui Keiyukōshū
 * Rank - A-rank
 * Range - Close
 * Targets - Singular
 * Class - Combat Genjutsu
 * Usage - After locking an opponent into a grappling maneuver or a restraining seal, the initiator exhales a foul invisible miasma at point blank range. The malodorous exhalation registers to the target as a vile lingering stench, which immediately saturates his central nervous system with the user's dark chakra.
 * Effects - Target instantly experiences visions of a hideous specter that appears and physically binds the target's appendages and torso. The target almost immediately becomes incapacitated. Total paralysis, physical pain, and mental disorientation sets in. The victim remains unable to move or control their chakra until they are released by the user or an ally.

Origin

 * I've always been fascinated with genjutsu and disgusted by how Kishi has neglected this important part of the Narutoverse. I've wanted new types of genjutsu delivered through other senses, since most genjutsu is visually activated with a few sound based ones. I've explored tactile genjutsus in other characters. I've wanted to do an olfactory or gustatory genjutsu. I couldn't fathom how to deliver taste based genjutsu in a combat convincingly, so I focused on sent based genjutsus. Lots of humor could be injected into this type of genjutsu, which is why I included "Demonic Illusion: Abnormal Underarm Odor." When my characters defeat someone with body odor I wanted it to be a little less contrived than Kiba vs Naruto. In an effort to be a little more thorough than kishi has been, I divided the different types of genjutsu into more delineated categories. Hopefully, I succeeded.

Inspiration

 * Binding Illusion: Neuromuscular Havoc was inspired by a real life story. A woman fell from a horse. Her family took her back to the house. At first she seemed only to have a bruised thigh. However, later on the pain became so bad they took her to the hospital. Her condition worsened and the doctors couldn't diagnose her. The pain deepened until just cloth on her thigh was pure agony. Her vitals became unstable. They feared the worse. The family came to pray over her. During the night she had a visitor. The next day her symptoms abated and her condition improved. She was out of danger. No one knew the visitor. The family decided he was an angel. The doctors remained puzzled at her ordeal. They concluded she fell into a feedback loop where muscular nerve signals fed back into tactile nerve receptors, traveled to the brain, amplified, wash, rinse, repeat. They were left scratching their heads.