Haborymolus

Haborymolus (, Habōrīmoruasu; lit. "Sinful Coronation: Ordained Priest Robes Dyed Black") is an advanced transformation that's considered to be a combination of multiple transformations and supplementary abilities belonging to Devil Slayer Magic that's forged through the immense and versatile powers of Enchantment, giving birth to an arcane power that's on its own level — manifested in the form of diabolical armor matching the user's respective element(s).

It's considered to be alternate "final form" of sorts, making it a possible equal for the likes of Underworld Tyrant Mode and Devil Synchronization respectively. However, some users have stated that the transformation itself is just an advanced form of Contract and it's slightly weaker than the aforementioned. This makes it debatable of whether it's the most powerful transformation belonging to this category of Slayer Magic or not. Regardless, it's highly favored amongst users because it doesn't impose the same aftereffects as the other two.

Supplementary Abilities
Enhanced Devil Slayer Magic: One of the main benefits of this transformation is the natural enhancement of one's Devil Slayer Magic, its output exceeding the standard high-level spells and magic by great amounts. This is mainly due to it being the amalgamation of multiple abilities and transformations belonging to said category of Slayer Magic, each one having some sort of boosting effect, and further refined under the effects of Enchantment. It should also be noted that the user temporarily becomes a literal embodiment of the element(s) at their command due to wearing it as armor in concentrated amouts, calling upon it in great quantities, similar to a certain race — something other transformations and abilities failed to do before when used. It should be noted that the "purification" aspect belonging to this magic becomes more notable, as the element in-question gains a lighter color from the norm, making it extremely hazardous to those having demonic elements — either lethally damaging them or exterminating them in a single go, regardless of their power level. In this state, the elements are also of completely nullifying all forms of Curses, Magical Barrier Particles, Black Arts, and other techniques containing "evil intent". Not surprisingly, users are also able to absorb their respective element(s) in large quantities — so much so that it's considered impossible through normal means, regardless of their skill level, and are able to do so from various sources; this would mean, Elemental Magic and Slayer Magic are susceptible to this skill, making the transformation a bane to all elemental mages and Slayers respectively. Typically, the user becomes totally immune to the elements they command — quite rare for a transformation, ability, or a magic to possess, furthering its status as a bane to said mages. The destructive scale of each spell under Devil Slayer Magic is magnified immensely to the point that a user can destroy large areas in a single strike while temporarily affecting conceptual and imaginary forces, such as time, space, dimensions, and the like — inadvertently creating various phenomena that can affect the world itself in unusual ways.

Immense Magical Power Amplification: As soon as the user employs their respective Haborymolus, they receive an absurdly massive boost in magical power — which is sometimes more than what the typical body can handle. This points back to the aforementioned detail of this transformation being the culmination of multiple transformations and abilities, which is further refined through the effects of Enchantment. The levels of magical power is said to exceed the ones afforded by other similar transformations, but is dependent by what combination used to achieve this state, thus it varies from user-to-user. If one were to estimate the standard amount of power this transformation grants, it would be equated to an skillful and intricate form of physical and magical enchantment given to a member of the — one of, if not the strongest group of mages in all of Earthland. The elemental armor constantly absorbs all forms of energy to keep itself stable, thus the user's power may rise the longer the transformation is used while allowing them access to an unlimited source of energy. Users often take advantage of such an aspect to unleash the Diabolical Extremities multiple times, something that couldn't be done in their Devil Synchronization; this crucial point makes others believe that this transformation is much better than the former. It's said that the user is also able to utilize Magic Barrier Particle in larger quantities as well, implementing it in the same way as Eternano; due to this, it's possible for the armor to become much deadlier than norm if the energy source is shifted to this one.

Longinus Smasher (, Ronginusu Sumasshā; lit. "Holy-Demonic Forces Unification Paradox"): The Longinus Smasher is the user's respective technique, born from their level of mastery and understanding of their respective Devil Slayer Magic; in a sense, it's the culmination of all their combat experiences using such a magic — serving as the "embodiment" of their status as an Exorcist Mage. While this makes it similar to the Diabolical Extremities, the two have a very notable difference. Unlike the aforementioned, the user won't be in danger of transforming into a demon and it doesn't consume much power, making it spammable similar to the Magic Ray, Magic Ball, and the Surging Dragon Fist respectively — basic techniques that utilizes manipulating eternano to certain degrees. The drawback is that the technique won't be as powerful, thus equated to the levels of the Secret Arts. It's often implied that, because of the armor enhancing the destructive powers of one's Devil Slayer Magic, that the Longinus Smasher of each user will be extremely effective. Though this is true, it's only because the attack is concentrated and confined to make proper use of the various energies being flown through the armor itself, unlike the Diabolical Extremities technique, where its indiscriminate, a bit uncontrollable, and uses too much energy all at once. As the name would imply, the Longinus Smasher is able to induce paradoxes because it's normally made up of contradictory forces (i.e. Magic Barrier Particles and Eternano in most cases). These happen at random and can affect anyone or anything sans the caster; this makes the technique a double-edged sword of sorts, as it has the potential of causing friendly-fire. One thing that's consistent about the technique is that it's always related to the element utilized by the caster, making it easier to predict what paradox will occur when used going by what their element does in normal circumstances. In terms of naming, the Longinus Smasher is usually related to various aspects of the underworld: ranging from specific locations, to people affiliated with it, to conceptual events relating to it.

Trivia

 * Typically, this serves as the Devil Slayer-equivalent of the Sigurðr; however, it's methods of employment is rather different, requiring a combination of pre-existing modes and transformations to achieve. Due to this, it's more similar to the Scaleshift: Diabolos Dragon — which is more powerful than the standard Dragon Force and possibly equal to Draconic Sovereign, thus can be considered a near-equal to the Devil Synchronization and Underworld Tyrant Mode respectively. In lieu of this, the power of this transformation is dependent of what combination of abilities and other transformations are used to compile its being, thus its level of strength is questionable at best.
 * It's obviously based on the various Sacred Gears seen in the light novel/anime series, Highschool DXD — specifically, those having Dragons sealed inside of them. To an extent, it's also based on the Ice-Rending Divine Raiment utilized by in the latest chapter of the Fairy Tail manga.