The Vaults are the archives of Iacon, located in the High Council Pavilions. Data from all over Cybertron is collected there, which is analyzed and sorted by the archivists, then stored onto "cassettes", and finally put away by Diagnostic Drones for future use.
Arriving in front of the gates to the Vaults, where Zeta Prime had taken the Omega Key, Megatron tried to force the doors open the usual way by infusing them with Dark Energon. They didn't budge, but instead another hologram of Zeta Prime appeared. The Prime claimed he would consider sparing Megatron's life if he'd surrender now, but Megatron declined, ordering for the Decepticon airforce to come in and blow open the gate.
Once inside, another hologram of Zeta Prime popped up to give another "Desist or die!" speech which Megatron again ignored. A little further into the building, Megatron and his unit found a stray Decepticon and were witness to his execution by the primary security measure in the Vaults: ceiling stompers. Kindly though, whenever they were about to come down the targeted piece of floor lit up, so the Decepticons had an edge to reach the chamber in which Zeta Prime had holed himself up. Megatron almost could lay his hands on the Omega Key, but Zeta Prime thwarted his plans a last time by taking the key under a forcefield in the center of the room from which he could safely control the entire chamber. Using ceiling stompers and holo-brutes, Zeta Prime had the advantage until he needed to recharge the equipment, leaving it vulnerable. The Decepticons immediately took him out, and Megatron finally laid claim on the Omega Key, ripping it out of a dying Zeta Prime. Yet, as he lay dying, Zeta Prime notified Megatron that there was one little catch to the usage of the key...
Following the acquisition of the key and the activation of the Geosynchronous Energon Bridge, Megatron used the orbital gun platform known as Trypticon to target Autobot settlements on Cybertron, one of which included Zeta Prime's Vaults.
The Iacon Vaults were a place that stored numerous Cybertronian relics, such as the Forge of Solus Prime. During ancient times, Orion Pax was known to have worked at the Vaults of Iacon as an archivist. During the Great War, numerous class-A weapons were confiscated from the Decepticons and stored within the Vaults, which included a shield generator and the Spark Extractor. When Iacon fell to Megatron, all the items within the Vault were tagged with an Iacon homing beacon and launched into space by Alpha Trion, who had foreseen that Earth would be a vital battlefield and Optimus Prime would need the artifacts. Unfortunately, Megatron managed to uncover their location through the use of Project Iacon.
The Decepticons had the Spark Extractor snatched from them by the Autobots, but succeeded in retrieving the shield generator and the Forge of Solus Prime. More coordinates, decoded by the Nemesis itself, led the Autobots and Decepticons to find a phase shifter, the Apex Armor, the Resonance Blaster, and a cache of Tox-En. Optimus Prime and Soundwave then decoded the coordinates for the Star Saber and Omega Keys.