Sky-Shatter Runes

You're along the beach when you see a bustling caravan of merchants. Smiling, pouch of gold ready to feel lighter, you approach! The first merchant's shop to catch your eye is a quaint but vividly purple wagon. Approaching its rear, a smiling woman with powder stains of every color on every part of her leans out.
"Hello, dearest! Hyeh! You a drinker?"
You chuckle and respond, "It depends!"
A twinkle in her eye, she disappears back inside; moments later, she LEAPS from the cart, now holding a belt with jostling jars. They look hastily-attached and you instinctively brace to dodge a potential break.
She presents it to you with a flair, the sun making her squint a bit now that she's facing the ocean and the setting sun. She's bragging about the various potions it has, and its dazzling array of colors make it convincing.
You hear, however, the sound of breaking glass.
It's the volume of thunder, shaking the ground and the armor you wear.
The woman freezes.
The belt falls.
You catch it just in time, but the woman is unresponsive, and the sound of the breaking glass echoes.
You turn, blocking the glaring sun so you can see what happened.
There, in the sky, is a spiderweb of slowly-expanding cracks. It's about as far as clouds should be, and you see birds swerving to avoid them.
Then, an airship CRASHES through the sky, revealing what looks like a night sky in whatever world it came from.
Another.
And another.
Impossibly, three airships have crashed through the sky, and the setting sun's glaring orange has no effect on the ominous night sky behind the shatter.
A war-horn sounds from the centermost ship.
Roll initiative.

Utility

The runed armor immobilizes the wearer when activated, and it drains essence at twice the rate if the wearer must control an airship as well. With an organized military, pilots can be rotated for minimal impact; with a party, the toll is dire for heavy use.
What few have learned, however, is the adverse effect on the planes; when used jovially, the Weave can't maintain the material plane as effectively. The plane is theorized to be at risk of annihilation, but this is-- or rather, was-- in dispute. With the establishment of the Vault of Eons, a universal gag order was issued.

Inventor(s)

Utican Dwarves, whose race has been lost; all contact following the Calamity has been lost, and millennia have passed without a peep from them. They may have disappeared or simply gone into seclusion.

Access & Availability

Lost to the archives of war pacts and international treaties for generations, this armor was used readily in times of war. Now, with time having taken its toll even on the Vault's well-hidden spoils, few functioning sets remain. They were looted in secret, and rumors of petty territorial spats between the nations of the archipelago arise again...

Complexity

Many millennia before my campaign begins, the traitor god Igneel sabotages his kin by drawing the planes into an inescapable form of a Newton's Cradle; every so often, the planes will crash! The very boundaries that separate them weaken, and devastating blasts of energy erupt from these seams. The energy released in a natural collision is colossal, and as planes have no technical boundaries, their collisions are more akin to the generation of a mesh. There are nearly countless "seams" generated when this happens, as the two planes merge into a cacophony of ruin.
Unfortunately for the denizens of the material plane, the elementals whose kin are, essentially, harnessed for their power are of no peaceful disposition. Civilian or not, elementals care little in the target of their great vengeance.

Discovery

In a time of desperation, the Dwarves that populated the region now known as Utica found a means to replicate the phenomena. By heavily concentrating the Weave in a circle with a hollow center, they managed to create a "vacuum" in a small region; here, the boundary of the material realm was weakened. This power was transferred to runes, as they were famed for creating. When used properly, the runes sip from the wearer's essence, and a seam to the astral plane, the space between planes like empty space is between galaxies, forms.