Mirror chain reaction

Gudea Nasir took his cloak and stole out into the forest. It was pitch black, but he couldn't risk holding a larger lamp and being discovered. He had walked this path many times and almost knew it in his sleep. He ran to a small cave, pushed aside the bushes, looked over his back again to see if anyone had followed him and slipped in.
There were a few torches attached to the wall of the cave that were already burning. It smelled of musty leaves and stale beer. In the middle was a simple table made of a few perforated boards held together with a few plant ropes. There were a few blueprints on it, which a petite woman and two other men were studying.
The woman looked up briefly and greeted Gudea with a snappy: "Ah, it's nice that the gentleman is finally joining us!". Then she stood up and pushed one of the blueprints towards him: "Yarim smuggled the first designs for our gift to the magical today and when we have the parts, you will build the first prototype."

Mirror Rebels at secret meeting, 2,809 BEC in the Kuria-Digudri -

Short review

After the rebellion was crushed in the Mirror Battles in 2,820 BEC and many followers were banished to inhospitable regions of Idaka or retreated to more isolated islands of Uluriqi or the Tùgwlduin of Brictaelgis, they tried to maintain their cohesion underground.
Ten years after the execution of the martyr Samun Usir, the scattered rebels launched an offensive against the portals across Elaqitan starting in 2,810 BEC, which led to a devastating chain reaction in 2,800 AEC. The resulting natural disaster remained in the memory even after people fled to earth and still exists as a legend in many cultures today.

The preparations

Construction of a Haze prototyp by Blue Fairy 74 via Midjourney

In the ten years of their seclusion, the Magicless had adapted and traveled across the continents to get to know the portals, their peculiarities, the Elaqitanians and their cultures better. Their goal - the destruction of the portals - was still clearly defined.
You may be wondering why it took another ten years after the start of 2,810 BEC for the actual catastrophe to occur? Well, the rebels were very subtle. They gradually mingled with the locals on all continents. They made friends with them and they lived among them like a wolf in sheep's clothing.
Since they were used to using their minds without the use of magic and making something useful out of the little that was available to them, they invented a device for doubling resonance waves onto the input fields of the portals. They called it the “Harp of Wrath (Haze).”
The device had to be attached below the input field, which is why many rebels tried to inconspicuously smuggle themselves into the mirror mechanics' groups. They were welcome workers because they were hardworking and also worked for less money. In addition, they equipped the weapon with a dielectric made of liquid crystals that could redirect the light around itself and bring it back together behind it, making the device invisible to the uninformed.
Little by little they attached such devices to the portals all over Elaqitan. Since they had already learned how to use the portals before the mirror battles and caused little attention with their activities, they were able to travel back and forth quickly and unnoticed.

The catastrophe

Once attached to the portals, the "Harp of Wrath" began to record and store the vibrations generated by the input field. The more often the control panel was used, the larger the recording became. Of course, there were portals that were used more often than others and there were portals that had the Haze applied to them earlier than others. This was all an elaborate plan and based on many calculations.
When the storage capacity was reached, the next use of the control panel triggered a pulse that created a protective shield around the mirror and simultaneously opened the portal to a location that the rebels had previously programmed into the Haze. The pulse overrode the original control panel and sent the weapon's stored code to the portal as its final target. Any further use of the mirror was impossible and destroying the mirror from the outside or inside or deactivating it was not easily possible, even with magic. So that the plan could not be thwarted, the portals that were used more often were of course only equipped with the haze later. These gates all closed shortly before the catastrophe.
The Elaqitanians could not see where the portal led to and therefore did not anticipate the risk of an approaching threat. If you looked into the protective shield, you saw nothing other than a consumed self of yourself. Now, it was really a mirror - but its interior led to the depths of the Îbimiqùrií, the largest ocean of Elaqitan.

Vám Lish stared at the portal that simply wouldn't open and showed a twisted grimace on his face that seemed to be laughing at him. He pressed the control panel several times without it changing anything. A line of people was already forming behind him who also wanted to use the portal and were watching the spectacle, some with amusement and some with amazement. "Where in the gods' name are these damned mechanics when you need them?" he cursed and ran into the adjoining guard's room.
Just as he snapped at one of the guards and shouted: "Hey you - yes you, come here! The gate needs to be repaired!", all he heard was the thundering sound of a roaring wave that swept everything away...