Zerenda's Fangs

Developed purely with the objective to tear down the steep walls of Saratheas during the Cleansing, this type of siege engine is not only vicious-looking, but also highly effective for its intended purpose. Not only did it install further fear in people's hearts even after the Cleansing, it also fundamentally influenced any following conflicts within the old cities of Ivendarea. It's a machine of destruction, and the different variations it comes in today show a history of mercilessness and cruelty against one's own citizens that has no rival.

Preconditions: A new Capital for Zerenda's Ivendarea

It was the year 8 after Zerenda's conquest of Ivendarea and the death of king Fannyel. Zerenda had made himself at home in the cold northern capital of Canwyl. The first wave of curious followers from his homecountry had already arrived in Ivendarea and settled down in the towns ransacked on the eastern coast of the country. Soldiers were still present everywhere trying to break the natives will to fight back. The country was far from being calm, the nyr fought back with all they had, and Zerenda was growing weary. He also didn't like Canwyl as the capital much, on the one hand because it seemed far off from the rest of his new lands, and on the other hand, coming from a rather warm country originally, he didn't like the cold at all.
While Canwyl was a beautiful and impressive city as such, Zerenda had cast an eye at Saratheas. He had been there a few times for his war efforts, and he was convinced that it would make a much better capital - and he decided to turn this thought into a practical plan. If successful, it would potentially also help with further lowering the moral of the most resistant of the nyr.
Within a few months Zerenda had gathered his forces in the valley of Saratheas and ordered the priests to leave the city - but they refused, barricading the doors and shutting themselves in. Saratheas being a temple city it wasn't equipped with a large military force or weapons of any description. But the location of the city was more than advantageous, at a steep cliffside, only to be reached via a narrow mountainpath.
Several times Zerenda's men tried to approach the city, coming from different directions and scaling the mountainside, but the inhabitants of Sartheas knew how to defend themselves. Causing landslides, smashing rocks down on the soldiers, pouring hot boiling oil - Zerenda took considerable losses before realizing that he had to go new ways to conquer the city.

Weakness of the Trebuchets

Trebuchets were a common sight with Zerenda's troups, and it was trebuchets that destroyed large parts of Beldran during the initial invasion on the east coast. They were present in the valley of Saratheas as well, but it soon turned out that they couldn't be moved high enough up the mountain to be effective without running the risk of losing them against the Sarathean's defenses. From a still safe distance the trebuchets only managed to hit the solid mountainface, not the walls of the city.
Zerenda's war engineers initially saw the problem in the trebuchets power: if there was a way to have them fire with more force it might be possible to reach the walls after all - although it would require months of testing and probably creating several prototypes. Initially Zerenda reluctantly agreed to this plan. If it took several months to come up with a better-working machine, they could use the time to starve out the city or potentially look for additional other ways inside.
After a couple of months two prototypes were presented. One immediately broke during the first test shots, because the forces applied to it were too strong for the wood used in its construction. The second prototype was promising, and it actually struck the walls - but from its safe distance it couldn't do enough damage to tear them down.

A different approach

Zerenda became increasingly impatient, and this is when yet another engineer suggested a different approach: modified ballistas. Ballistas were used in Zerenda's forces as well, although not as dominantly as the trebuchets, because they had less power and needed to be much more precise to effectively do damage. The engineer reasoned though that a ballista's trajectory was much more suited for Saratheas as their target, as it was straighter than the trebuchets ammunition. A rock flung with the trebuchet needed to be catapulted high in the air and was the most devastating when it then started to fall downwards again. The projectile of the ballista behaved very similarly to an arrow, with a much more flat trajectory. Yet, it wasn't able to develop enough force to tear down walls.
The engineer agreed, but then said that he could alter the design in a way so that the damage could be much more devastating. Zerenda allowed him to continue, and after another month a prototype was ready.

Mode of operation of the "Fangs"

The principles behind the "new and improved" ballista were two things: the modified arrowhead and the new return mechanism.
With regular ballista ammunition it was usually the case that it remained stuck in the target - but Zerenda's engineers in this case wanted to make sure that these arrows didn't only get stuck, but got anchored within the material of the wall. An intricate mechanism was integrated into the arrow - initially there was only one, to test if the idea behind the machine would actually work out. Upon impact a bolt within the arrowhead would be triggered, releasing three sturdy hooks that would dig themselves into the stonework. This would anchor the arrow in place - then, with a lot of manpower, the arrow would be pulled back by the chain attached to its base. The chain was a weakness compared to the regular ballista, as it weighed the arrow down and more force was needed to fire it far enough, but the experiences the engineers had made with the new trebuchets helped with adjusting the machine just right. Pulling the arrow back with the chain would, ideally, also tear a hole into the wall already weakened in its core by the spikes. This was the plan.

Final Adjustments

The first few test shots needed some minor adjustments, but after a couple of failed attempts, the arrow finally made its way to the wall - anchoring itself deep within the stone just as planned.
It worked so well actually, the arrow going so deep, that it turned out it was impossible to pull it back out across such a big distance. Arrow one was lost, stuck to the wall, as was a big portion of the chain supposed to bring it back. But the engineers had one more idea and added a vial of a specific acid into the design of the arrowhead. It was created to particularly affect the stone that the walls of Saratheas had been built with, a slightly porous sandstone that would absorb the acid like a sponge and then crumble and dissolve. The spikes were furthermore hollowed out, like needles or a snake's fangs, to dispense the acid as deep and far into the stone as possible.
When the second arrow prototype was ready to launch, more than 5 months of siege had passed, and still the Saratheans wouldn't surrender. Zerenda decided to give them a final chance, but when they refused, he ordered to fire the new arrow. After it had hit the wall, not too far from the first failed attempt, nothing happened for several minutes. The engineers asked the king to be patient - and then suddenly a dirty yellow smoke started to rise from the point of impact. Zerenda gave the orders to pull the arrow back - and this time it worked. The arrow came loose and could be retrieved, in the process tearing a big, steaming hole into the wall of Saratheas. It was a relatively quiet process, and so the Saratheans initially didn't notice that the humans had started to break through the walls. Zerenda ordered to continue, the arrow kept being refilled with poison, and the new trebuchet was readied as well, to strike the weakened walls when the right moment came.
At the third strike with the arrow the Saratheans started to notice that something was wrong, that the wall had started to crumble - the acid created a biting, harsh stench that had caught the citizen's attention. Piece by piece the outer wall was torn apart, and still on the same day it finally fell, causing a panic within the city. With the outer protective layer of Saratheas gone, it was easier now for Zerenda's soldiers to see what was going on above them as they stormed the mountainside again - and the way was also clear for further trebuchet attacks that could now target buildings within the city limits, causing more panic and distractions.
It took several more days until Saratheas was fully under Zerenda's control, but victory was brought to him by the siege engine later even named after him and its similarity to a snake driving its venomous fangs into an unsuspecting victim.