"Hydra"

The MK-I HYDRA is a fission-powered rail-gun, presumably the only one of its kind to ever function during a war, specifically, the War of the Holy Gates. Although the HYDRA is the only fission-powered rail-gun to ever be constructed, many declassified documents from Lucifer's castle state that numerous attempts have been taken in prior years.

Origin
The idea of a fission-powered rail-gun, or rather the precursor, a combustion-fueled rail-gun, was first proposed by physicist and strategist Dimostenis Antonitos, of the Royal Institute of Lucifereæ. Antonitos proposed that a suitably contained nuclear core could be used to manually create a powerful source of combustion for firing shells.

Lewis-Grechorio Model
The HYDRA was originally planned to have been a stationary artillery gun, with four stabilizers extending from each corner to counteract the high recoil, but this design was scrapped after two failed attempts at firing the mechanism, both of which resulted in the "dummy" high-explosive shell exploding prematurely, killing all 80 members of the artillery crew.

"Demon's Wings" Model
The HYDRA's secondary model was a much more elaborate feat, which saw the large artillery mounted, on both sides, with two six-column stabilizers, which would pierce the ground as to provide a more stable form of counteracting recoil. The main issue was the weight of the stabilizers, during which an imbalance could upset the entire artillery. After several re-designs, the stabilizers were engineered to fold horizontally on the artillery, thus having the nickname "Demon's Wings" bestowed upon the gun. While the first trial failed prematurely, due to a malfunction in the hydraulics which lowered the columns, the second trial failed with a costly consequence. Considering that the stabilizers extended into the ground, it was not clear as to gauge how deep each column dug. As a result, there was initial reluctance to fire the mechanism, but the reluctance was soon quelled under "persuasive measures". When the mechanism fired its "dummy" shell, two of the columns had failed to penetrate the ground more than a few mere metres. This resulted in the artillery listing severely to its right, then under the monumental stress of the gun, the other stabilizers snapped like toothpicks and the machine crashed to the right, resulting in 23 casualties of the crew. Due to the futility of the device, and with limited funding to produce a second-design, this design was scrapped.

Johann-"Tank" Model
After heavy re-evaluation, a tertiary model was decided, one which involved scaled-up tank tracks as to provide a means of slow, yet continuous movement for the large gun. Due to the large area of the tracks and base, no exterior stabilizers created. It took two weeks alone to produce a single track for the quad-tracked base, and this was noted as being highly inefficient, and quite possibly a reason of the design being scrapped. During the first trial of the Johann-"Tank" Model, two of the tracks became misaligned, and consequently, the gun could not be fired, as worries of de-stabilization (stemming from the "Demon's Wings incident) outweighed the assurance of a safe firing. On the second trial, the gun was autonomously moved and fired successfully, which most certainly was a cause for celebration. However, it was noted that the overall process of procuring the quad-tracks, base, and construction of the gun took around 36 weeks, highly inefficient during wartime standards. It was also noted that the cost of the entire operation was sum of around 22,000,000 Sikarli (£31,609,195.40), and thus, the design was scrapped on the basis of "inefficiency and costly to such an extent that is is not feasible in mass-production."

Mathers-Alco-Model
Perhaps the most infamous design in the timeline of the HYDRA, this design was structured in that it would be moved along railways, operating as a normal rail-gun would. However, the design itself is not infamous, it is rather the result. During the process of constructing the railways and gun, several malfunctions were noted, thus slowing the construction process considerably. But after 15 weeks, the railways and gun were assembled, and testing was set to begin. On the day of the first, and only, trial, a fatal mistake in the labeling system resulted in the shipping on a 47-centimetre plutonium shell being shipped to the site, instead of a "dummy" 35-centimetre high-explosive shell. This could not be noted in the spur of the moment however, since the gun was loaded at the aft, where the barrel was considerably larger than the dilating tip, which was 37-centimetres wide, structured this way to create additional air propulsion. When the gun was fired, the plutonium shell scraped the edges of the ever-dilating barrel, until it reached the middle of the barrel. At that point, from the accumulating friction, the sensitive plutonium shell went super-critical, and exploded, resulting in the entire machine disintegrating, and casting a five metre deep crater into the ground.

The total number of casualties is unknown, but is estimated to have been around 1,254 deaths and 10,913 injuries as a result of this explosion.

The blueprints was destroyed, with the HYDRA project halted for five years, and the architect executed under failure to take into account safety.

Section I
After the "Mathers-Alco Incident", many were reluctant to ever construct, or even design another model for the HYDRA, and it seemed that such a feat would not be feasible. Enter Walther Exconiuo, a renowned architect and military strategist. Exconiuo proposed that in order for the HYDRA to maintain stability, the "Johann-'Tank' Model" would have to be revisited. Exconiuo designed a lower base and senio-tracked mobility system, along with two external supports, one in the front and one in the back, that could be automatically lowered when the time came to fire the mammoth machine. Exconiuo also postulated that while previous models of the gun were rather compact, he attributed this to a lack of an aiming system. He theorized that a sort of "crane-mechanism" should be implemented into the design in order to provide an exact measurement of range. The base was thus extended to a rectangular shape, as to provide more stable support for the extra crane-mechanism. On the subject of how the mechanism was to be moved efficiently, Exconiuo drew on the works of aforementioned Antonitos, claiming that housing an internal nuclear reactor could function as both a means of combustion and energy.

Section II
While the thought of housing a reactor within the mechanical hull of the gun was welcomed, the main obstacle was how the reactor would be shielded from any exterior impact, such as shells or bombs. The module of the gun was constructed to house only the necessary cogs and gears, with minimal space allocated for any other machine. An early idea was that while the reaction would be attached to the exterior of the gun, but would be covered by plates of 600mm thick steel, but this idea was unconventional in that a large enough explosion from outside interference could either blow off the plating, or jostle the reactor in a way that could result in it going super-critical. A secondary idea, postulated by Exconiuo, was proposed in that the base of the gun could be expanded in order to house the reactor, after all, the thick machinery and cogs could theoretically protect the reactor, especially in the case that all the parts were made from steel. This secondary idea was accepted, but with one minor inconvenience; the speed at which the gun traveled would lower, since an interior reactor meant thicker plating for the exterior. During the national Convention of Royal Theorists, it was decided that the "Walther-Excon Model" would be used as the official design of the HYDRA. (Draft.)

Construction (Timeline)
While the decision on the model of the HYDRA was decided in a majority to be the "Walther-Excon Model", approval was still needed from His Royalty, Lucifer.

First trial: 1032 A.D
The first trial of the then-experimental HYDRA, known as the NPRG, took place on March 25th of the year 1032 A.D, with the location of the trial being along the Surimanien River in Lucifereæ. At approximately 10:35 AM, the escort that carried the plutonium-tipped artillery shell arrived and began the process of unloading the near-unstable shell.