Infernal Body

Infernal Body (業炎によって偽造悪魔体 (インファナル·ボディ), Infanaru Bodi; lit. "Satanic Body Forged of Underworld Flames") is a supplementary spell derived from the basic aspects of Fire Magic; though it belongs in such a category, it's usable by various Mages well-versed in either fire manipulation or any magic dealing with the element, including Lost Magic such as Slayer Magic or Subspecies Magic such as Sun Magic.

Overview
This spell allows one to gain a form of immunity using the element of fire; however, this trait is shown in all elemental magics — thus not exclusive to just fire. In order to properly execute this simple spell, the user ignites the eternano in their bodies — done through high-paced friction & spreads it all over the body at a rapid pace. This causes it to gain momentum, thus igniting into small conflagrations. The small embers causes the body to slowly heat up until reaching a certain point. By adding more of their magical energy, the user excites  both the body's now-abnormal temperature and the embers even more until they become one, amplifying each other in an endless cycle. This causes the user's body to be alighted as a result, a clear sign being flames igniting from various parts of the body. At this point, the body's temperature exceeds its original point. To a non-fire mage, this can be seen as dangerous — the risk being that they could burn themselves alive or evaporating all the water in their body, becoming de-hydrated as a result. However, this serves as a different story to those well-versed in the element of fire. It's stated that it's difficult to get near to a person who uses this spell because of the intense heat it gives off.

The main purpose of this spell, as explained before, is to give its users a form of immunity. Because the user is clad in flames and gives of intense heat, they're protected from most spells and projectiles such as bullets & arrows. In fact, such spells and weaponry would inevitably be burned to its core upon making contact with the user's body clad in this deadly spell. Only high-levels spells can possibly affect the user, but to a certain extent. This spell has other usages that's only limited to the caster's imagination because they're manipulating pure fire — albeit contained in & around their bodies, thus having no given form. One such possibility — albeit a common one, is the boosting of their other fire-based spells. It's recorded that spells influenced by the effects of this one are magnified, becoming twice as powerful & destructive. This gives it the ability to overpower stronger spells while dealing wanton damage to their surroundings, covering it in a sea of flames. Another possible usage is enhancement of one's martial combat skills. By focusing the flames to a certain part of the body — alighting it as a result, the user is able to burn their opponents with each strike while dealing heavy damage. It's said that if the opponent were to ever dodge a blow covered in this spell, they would surely be affected by the heat coming off of it. Physical attacks cloaked by this spell is able to aggregate injuries and cause second-degree burns.

Albeit something not normally seen, the user is able to utilize the spell for flight. This is similar to Flameflight, albeit with stark differences. Unlike the former, the user utilizes the flames that they already have. By propelling the flames from their feet or hands, they can sub-sequentially fly in the air. It's known that while in flight, they are covered in a flame-like aura that protects them from outside influences. This makes it difficult for most beings to come near them. Because the heat gets even more intense in flight, as the user is constantly igniting magical energy to stay afloat — they unconsciously create vacuums, which is caused by the heat severely affecting the airflow. Such vacuums can draw beings in — causing major damage to them as a result, or create slipstreams, accelerating the user's movements even further. However, as this usage expends more magical energy than Flameflight, it doesn't long. But, when this spell is mastered, it's possible to lengthen the flight time.

In short, this spell has many advantages that it grants the user. Though the spell cost much magical energy to employ for beginners, it serves as an asset to those that are able to master it. This spell serves as a staple to most fire masters, seeing it as a sign of their given mastery of the element in-question.