Engine Prototype #4 (Catastroph)

Full Item Description
Engine Prototype #4 stands at approximately 50 meters tall. It is vaguely humanoid in appearance, with a massive hump and its frame bent over to allow quadruped movement for stabilization. It shines like a star as its iron hull-plating is coated with a wafer-thin layer of highly refined mithril.

History

Catastroph. That's what we called it. Well, it was actually known as Engine Prototype #4, but only the damned project heads and that batty Artificer Clauz actually called it that. The rest of us, we little workers and soldiers, the technicians and wizards who were a part of the Prototype #4 project couldn't help but call it by a real name. Some of the men and women on the construction site didn't like what we were doing. They thought the engine was too destructive. Regardless of how we felt about it or what we called it, we helped to create it. One of the largest mechanical undertakings ever, and we were part of it. The only real way to describe it was amazing. Day by day, for months, we toiled. We welded and bolted, ran wiring and connected cogwheels. It took almost a full year, but by the end we had it.

It was marvelous; a mechanical and magical combination that would stun the entire land of Terescence. With it, the Federation would finally bring down those pointy-eared Elven bastards. Nothing would stand against our creation...

~ Journal of Tyler Harper, Summer 765

The Arcane Mortar is a rather complex device. Firstly, there are tiny fibers running all over the iron-plated hull of Engine Prototype #4. These fibers are specially spun strands of mithril, designed to conduct magical energy. The strands run all over the hull, meeting roughly in the center of the engine where there is a large crystal used to store any magical energy directed at the hull. The energy can remain in this stone almost indefinitely, until it is released, of course.

This design makes the Engine all but immune to the effects of magic, either as spells or in an arcane-infused weapon, as the energy is almost always with reflected off the paper-thin layer of mithril covering the hull, or drawn down the fibers into the storage crystal. If the magical energy does make it through the hull and fibers however, the machine will take substantial damage, as the delicate balance required to keep the storage crystal stable requires a lack of magical protection in the Engine and indeed, a lowering of the natural resistance of the iron itself.
Once a substantial amount of arcane energy is accumulated within the storage crystal, the Engine will release it in a time of need, as a radial blast exploding outward from the machine. This raw arcane energy will deal acute amounts of destruction within the blast radius, annihilating walls, buildings, vegetation and likely killing any and all beings in the area. As this blast is a defense mechanism to prevent the Engine from being swarmed in an attack, the Mortar will make it impossible to deploy the Engine with our own troops, lest they be caught in a potential blast...

~ Production notes on Engine Prototype #4,
Artificer Jean Clauz

We heard the thundering and crashing long before we could see it, despite its immense size, and... text too obliterated to understand ...broke through the forest into the clearing that contained the city, a collective gasp was heard all across the city walls. What we saw was a hunch-backed humanoid, made entirely of metal...damaged text ...towered over the soldiers in the clearing before the city, standing perhaps fifty meters into the air. Some of the Guard actually fled their posts, not that it did them much good in the end... text too illegible ...strike team of adventurers attacked the mechanical monstrosity...illegible ...dwarf actually managed to mount its back, though it appeared as though small cannons sprang out of its hull...illegible ...seemed to have no effect, most just crackled along its hull-plates and then dissipated as if drawn inside...several paragraphs illegible ...machine grew brighter, almost seeming to glow from inside, then a massive blast ripped through the clearing...illegible ...dwarf was thrown through the air from the force of it, along with the other adventurers. I'm dishonored to say I began to flee at this point with the rest of my unit, but...illegible ...still only just made it off the walls before the shockwave struck the walls, utterly destroying them and throwing massive chunks of stone through the air. Few sentences lost...remember seeing a shape fly through the air just before I was knocked unconscious. burnt page ...Story we got later was that a fellow of the adventurers arrived with an explosive powder and dropped it from a flying carpet...illegible ...machine was destroyed, but Cullebra was lost as well as thousands of my race. I praise Gaea I was lucky enough to survive...

~ Report of Guardsman Seran Rellia, after
the destruction of Cullebra

Magic/Cursed Properties
I'm giving these rules as I ran them, feel free to change numbers or determinations as you feel fit.

The Arcane Mortar is essentially governed by random chance.
When Catastroph is hit with a magical force, whether from a direct spell, or from a magical weapon, a d6 is rolled.

1, 2, 3) Energy is absorbed. I took the level of the spell or effect and added three times that amount to the current storage level of the Mortar.

4, 5) Energy is reflected at caster/wielder.

6) Energy breaks through plating and fibers to strike the interior of the engine. I applied double damage/effect for anything that made it through.

Once the Mortar storage crystal reaches critical mass (I went with when it was dramatic, but an arbitrary number such as 150 could be used), the energy is released in a blast with a radius of 40 meters. This damage is raw arcane energy and as such, it ignores any form of damage reduction or decrease for the strength of any effected beings, structures, etc...