Gas Devil Slayer Magic

Gas Demon Slayer Magic (ガス鬼殺害魔法, Gasuoni Satsugai Mahō) is a Lost Magic and a Caster Magic and is a type of Demon Slayer Magic used by Sakura Yakumo.

Description
Gas Demon Slayer Magic is a type of Demon Slayer Magic that differs from the others of its kind as it allows the user to produce several different kinds of gasses in order to harm the opponent. Upon activation of this Magic, the user releases a red, translucent, poisonous gas throughout the area. The user is then able to command the poison to expand and grow until it reaches the victim, making it almost impossible to avoid it. The poisonous gas that this Magic creates is dangerous when inhaled and nearly lethal when exposed to the skin as it has a decaying effect to it. There is seemingly no way to avoid it, and as it is thicker then most poisons, it cannot simply be dissipated by Magical Energy. In this form, Gas Demon Slayer Magic is its most deadliest, as it has no limit to how it grows and expands; however, it is still under the user's command. The user is also able to cause the gas Kansen creates to take on properties of various other toxins in order to further inhibit their opponents.

The user is able to generate these gasses from anywhere on their body, even gainingan immunity to other airborne toxins.The gasses produced by Gas Demon Slayer Magic are incredibly potent, although its usage is draining on the user's body. The user can also use this magic to turn their body into a corporeal form, similar to the Demon Teacher, Luminare, and can even ingest other gasses or poisons in order to regain their strength.

Spells
Gas Demon's Roar (ガス鬼殺の咆哮, Gasuoni no Hōkō): The user generates a mass of gas in their mouth before spewing it outward toward the opponent. The gas then takes on the properties of neurotoxic venom. In this form, the Gas Demon's poison can cause damage to the opponent's nervous system. It also causes an inhibition of neurotransmitters resulting in muscle paralysis and the opponent losing control of their body.

Gas Demon's Sting (ガス鬼殺の剣, Gasuoni no Ken): By thrusting their limbs forward, the user can shoot forth a poisonous gas that takes on the properties of hemotoxins. In this form, the user can utilize the poison to cause severe hemorrhage. The poison also hinders the opponent's blood from clotting, making it extremely difficult if not impossible for the opponent to continue fighting after receiving several wounds. The poison can degenerate organs and can even damage the tissue of an opponents body causing limbs and other parts of the opponent's body to begin rotting away due to not having any blood flow.

Gas Demon's Speed (ガス鬼殺の速,  Gasuoni no Haya): Coating their body entirely with their poisonous gasses, the user's body becomes lighter and they bcome able to travel short distances for brief periods of time. During this movement the user becomes impervious to physical attacks and leaves a trail of poisonous gasses in their wake. This poison is harmful to the magical reserves of whoever comes into contact with it as it causes them to painfully "bleed" their Magical Energy into the atmosphere. This spell is particularly useful during a large-scale battle as it can cause many of the opponents to become weakened quite quickly, although the same can be said for the uer's allies.

Advanced Spells
God-killing Infection (神殺感染, Shinsatsu Kansen): Is Sakura Yakumo's strongest spell. Upon activation, she is able to produce a gas that moves towards the opponent at a moderate speed, much like a predator stalking its prey. After entering the opponent's body, through various means, the gas begins to controls the signals that the body sends to the brain, allowing Sakura to change the target's reliability on their own body, making fighting a very hard, if not impossible case. This poison causes the opponents reflexes to drastically slow down, as well as giving Sakura control over their limbs. With this spell Sakura can make her opponent's move their leg, for example, if they would try to move an arm, or cause them to not be able to move at all. This ability grows stronger over time, as more gas enters the opponent's body, and Sakura can eventually make the opponent feel pain without any source, let them move out of their own free will or even control subconscious functions of the body, such as the beating of the heart and the workings of other vital organs. If one would remain within Sakura's effective range for a large period of time, they will lose total control over their body, and will be forced to submit to Sakura's commands. The gas, however, instantly disappears once Sakura is knocked out, giving the opponent the control back over their body.


 * God-Killing Infection: Finale (神殺感染: 決勝, Shinsatsu Kansen: Kess​hō): The only known offensive spell of Sakura's Advanced list. This changes the structure of the gas in such a way that it becomes highly corrosive, being able to melt through solid metal with ease. Only Sakura herself is immune to this gas, which makes it dangerous to use when her allies are around. Another disadvantage to this spell is that the normally invisible gas now turns into a bright violet coloration, and spreads around Sakura in a similar manner to that of an inferno. This makes it easier for opponents to avoid and outrun the gas, but does give Sakura a vulnerable defense against short-range attacks, as her opponent has to enter the area of deadly gas in order to attack her.

Demon Force
Unlike the other Demon Slayer Magic Users, the user of Gas Demon Slayer Magic does not undergo a new transformation. When their Demon Force awakens from intense duress or agonizing pain, they gain access to a far more powerful toxin. While seemingly not as powerful, the strength of this poison makes up for the lack of any physical improvements. However, the actual and most dangerous ability of this Demon Force is that its ability of gaining control now no longer only extends to living creatures, but to anything else in the vicinity. This includes objects, the elements, nature, Magical Energy and even reality. Sakura has stated that her Demon Force's powers allows her to transcend the boundaries of what makes a Mage normal. To what extent this powers can be used is still unknown, but Sakura explained that if she would take control of something too powerful, she could possibly be destroyed by the resulting feedback. Using this ability Sakura could control the direction of the attacks aimed at her or her allies and even reverse them. In a more deadly twist, she could even let her own attacks pass through when they have been blocked or dodged. The way she controls inanimate objects resembles some sort of psionic skill, having the ability to turn anything against her opponent, from rocks to even their own clothes.