Volcano Devil Slayer Magic

Volcano Demon Slayer Magic (火山の滅鬼魔法, Kazan no Mekki Mahō) is a form of Caster Magic, Lost Magic and lastly, form of Demon Slayer Magic, which allows the user to harness and manipulate the power of volcano; in more specific way, the user of this Magic is able to fully utilize different forms of volcano's activity, such as volcanic ash, scorching magma, burning lava, etc.

Overview
Volcano Demon Slayer Magic is a sub-type of very rare Demon Slayer Magic, which can be utilized only by Demon Slayers (, Dēmon Sureiyāzu lit. Demon Power Users). This Magic allows its user or users to transform their physical bodies into a Demon's, more correctly, Demon Slayers are able to change their physical body to match the corporeal body possessed by Etherious, which also grants them various characteristics, that are typical for their demonic mentor.

In order to learn Volcano Demon Slayer Magic, the Etherious who passes on the magic to their student, modifies their Magic Origin with their own Magical Barrier Particles (魔障粒子, Mashōryūshi, lit. "Negative Energy Particles"), which changes how the magical energies circulate within their body, therefore causing the Etherious' main ability, the Curse (呪法, Jūhō), to enter the student's body momentarily; as a portion of their own power changes the student's magic into that of Demon Slayer. Continuing with this process, the Magical Barrier Particles of the student acts alongside the magic energy of the body in order to catalyze a variety of bodily processes when younger, therefore allowing the morphing of their physiology to a point where the individual has adopted some physical traits, as well as the element from the said Etherious.

Volcano Demon Slayer Magic allows its users to produce and control that, which can be called as volcanic element from any part of their body and can use it in melee combat or for other purposes. By means of volcanic element, people usually mention the power of lava or magma, which in their turn can be considered as a combination between the fire and the earth elements. However, it will be only the half of truth. The Volcanic Demon Slayers can utilize different aspects of volcano with their magic, which commonly called as Volcanic Materials (火山性物質, Kazansei Busshitsu lit. Volcano-Natured Materials/Substances): they can create a flow of burning lava and a barrage of scorching magma rocks, which is similar to Magma-and-Lava-related Demon Slayers and other Slayer Mages; Volcanic Demon Slayers are able to utilize some things, which are known to be volcanic ash and dust, a result of natural volcano eruption, which harness the volcanic particles, which were sent into the air, also on a serious note they can be used quite differently and the last, Volcanic Glass, the most unusual, but at the same time usuful thing, which is created on a hard terms by masters of Volcano Demon Slayer Magic. All the volcanic materials, which are incorporated in this type of Magic are different from their standard Magic counterparts, because of their demonic nature; Volcanic Demon Slayers can make their body a makeshift weapon unique to themselves and themselves only to the point, that they are able to even turn into their element itself, the form which is renown as the true essence of a demon's existence, and with their nature, it truly becomes a very serious tool in order to achieve the upper hand in different life situations.

Changed Physiology
As it was said earlier, Volcanic Demon Slayers like other Demon Slayers, have changed physiology, which is suiting the demonic mentor's one. First of all, it must be said, that they become totally invulnerable to the... volcano element. Yes, indeed, it can be unbelievable, but Volcano Demon Slayer Magic user is naturally immune to the effects of their own element, which means, that they're totally immune for magma, lava, volcanic ash-dust-glass. All these elements cannot even scratch the user's body, not to mention some serious harm. Moreover, they're immune to the volcanic materials that came from both their own person and to those from other sources, and can also consume external sources of their natural element to replenish their own strength and energy, which also an incredible thing, as Volcanic Demon Slayers can recover themselves with all types of volcanic materials, however, with each type on different levels. Also, Volcanic Demon Slayers cannot consume the volcanic elements, that they produce themselves, and elements must be consumed through the mouth.

Also, which is quite incredible and unbelievable too, Volcanic Demon Slayers are also immune to the effects of fire and earth natures, though they cannot control them. Because of their fire-natured elemental parts, which have a much hotter temperature, than fire, they don't give a single word to the Fire Magic and its other types. In addition to it, as somewhat mountain-related thing, Volcanic Demon Slayers don't react on the earth element at all too, because they can produce it in their own way. But, as it was mentioned, even if they have such dominance over the fire and earth elements, neither they're able to consume it, nor to control and manipulate. Also, it is hinted, that some Mages indeed can deliver some damage to the Volcano Demon Slayer Magic user with their fire and earth, but on what terms this happens is still unknown.

Interestingly, the use of Demon Slayer Magic, is corrupting a mage's souls to a sufficient enough degree for a demon to take possession of their body. Plus the contract that is signed when a mage starts learning this magic is another link that allows the Etherious, who is mentoring them, to take over their body. The more this magic is used, the easier it starts to become for the Etherious to take over. Also the repeated sharing of thoughts and emotions with an Etherious, which happens every time the Etherious tries to take over the mage's body, starts to drive the mage insane, a human's mind just not being capable of processing most of what goes on in a Etherious' head.

Element Traits
It was said earlier, that Volcanic Demon Slayers make a use of several, but close-related volcanic materials, which are incorporated in this Magic, and that which are different from standard volcanic elements. The generated volcanic materials can be manipulated in a wide variety of ways, with almost every element.
 * Lava (熔岩と溶岩, Yōgan to Yōgan lit. Solid Lava and Liquid Lava): Lava is can be utilized within two states - solid and liquid. In case of solid, it can be compared to somewhat magma element, however they differ from each other in terms of temperature and its base. Usually, solidified lava can maintain the temperatures from 650 to 750 °C (1,202 to 1,382 °F), but when a true master of this Magic makes his moves, he easily can reach the temperatures of 750 to 950 °C (1,380 to 1,740 °F) and higher. In case of liquid, the user is able to create a typical erupting lava, which temperature can reach the temperatures of 1,600 °C (2,910 °F); the usual utilization of liquified lava consists of creating the flood, flow and torrents from lava, in order to make an attack on their targets.
 * Magma (岩漿, Ganshō): Magma is a pre-state of erupted lava, as people usually know it. Magma is a complex high-temperature fluid substance, which temperatures are in the range 700 °C to 1300 °C (1300 °F to 2400 °F), but on some occasions and/or just by the wish of the user, created magma may be as cool as 600 °C or as hot as 1600 °C. Volcanic Demon Slayers is able to create quite solid structures with their magma, like different weapons, armory, etc. and something like magma-based bombs, which, when thrown, explode with not only the magma parts, but with solid lava too. The usage of such magma bombs can be compared to a real volcano eruption, but on a small scale.
 * Volcanic Glass (火山硝子, Kazan Garasu): Volcanic Glass is a final application of Volcano Demon Slayer's element. They're able to create it with their own powers, then they reach the masterful control over their magical powers and able to change the basic structure of their magma parts. With this element, the user is able to create a much stronger structures and things, which are on a far greater level, than its magma counterpart. Moreover, with Volcanic Glass, the user is able to somewhat mimicry other fellow Demon Slayers, for example, Iron, Sand, Earth Demon Slayers, etc.
 * Volcanic Ash & Dust (火山灰と火山塵, Kazanbai to Kazanjin): Volcanic Ash and Dust are both an essence of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm in their diameter, also this term rarely refers to merely all products of volcanic eruption, even with larger measuring. When utilized within the Magic, the user can create a big amount of Volcanic Ash and Dust, which they can utilize as tool for disguise and as quite handful combustible material; it should be noted, that the Ash and Dust are different from each other, though they almost look like the same thing. The Volcanic Dust of Volcanic Demon Slayers is also known to be more combustible, while the Volcanic Ash is more utilized within other purposes. Also, both of these things can be properly enhanced with Wind Magic, as this Magic will only blow the volcanic material away on great distances.
 * Volcanic Ash Soil (火山灰土, Kazanbaido): V.A.S. is an addition to the initial Volcanic Ash. The user is able to mix their ash with the earth element to attain a bit of control over it and also to have another, enhanced material to their magma-natured explosions.

All in all, with such twisted and different nature, Volcanic Demon Slayers are able to become a real threat to almost anyone, who even dare and can be considered as a person, who may give a real challenge to them. With their unusual nature and element, Volcano Demon Slayer Magic users are counted as the persons, who are superior to the Fire, Earth, Magma and Lava Demon Slayers and they're capable of defeating their inferior-like counterparts. On the other hand, with great power there is a great price and responsibility come. In order to fully, properly and masterfully utilize this Magic to its utmost limits, Volcano Demon Slayer Magic users need to maintain quite hard trainings and years of practise. It is no strange thing, that the only known user of this Magic, Yonshi Quarto, a man who lived for almost half a century, stated, that he trained hard enough to blood-and-sweat for twenty years of his youth, and then spent almost quarter of century to really understand and properly use his powers. Also, it is known, by the words of Yonshi, that there is no Volcanic Demon Slayer, who was or is able to attain the power of Dual Element Demon Mode (モード二要素鬼, Mōdo Niyōsoki) because of their nature, so it is hinted to be the truth.

Demon Force
Demon Force (デーモン・フォース, Dēmon Fōsu) is the final stage of the Demon Slayer Magic, though the exact conditions to invoke it vary from person to person. When Demon Force is achieved, the user's body completely turns into their element through saturating the insides of their body and the outsides with an overdose of Magical Barrier Particles, and their strength, speed, and demonic abilities are enhanced, improving their combat capability significantly. Demon Force greatly increases the damage done by standard Demon Slayer Magic attacks, and grants the user access to more advanced, powerful attacks. It also drastically enhances the user's physical prowess, making them far stronger, more resistant and faster, and boosts their demonic power, prompting it to violently become visible, taking on the shape of a demonic visage; when used at the fullest, the generated silhouette seems to gain corporeality, likely as a result of the immense amount of demonic power employed. As the Demon Slayer Magic user's entire body turns into their element, after activating Demon Force they are virtually immune to physical harm. They can allow any attack to simply pass through them or simply absorb the attack; it is essentially a boost in the demonic properties that Demon Slayer Magic provides to the user.

Volcanic Activity
Volcanic Activity (火山活動, Kazan Katsudō): More coming soon...

Trivia

 * This magic was aproved by Per-chin.
 * The author created this article, because of several reasons: firstly, he will need it, soon or later; he was slightly inspired by Alpha-chin's rush for Slayer Magic articles' creation too.
 * Originally, this Magic was named as Lava Demon Slayer Magic (熔岩の滅鬼魔法, Yōgan no Mekki Mahō). However the author wanted to create an interesting Magic, than simple Lava Demon Slayer Magic, so he suddenly decided to provide it with different features of volcano, which ended up in creating a far new element and its traits.