Helmet of disjunction

The helmet of disjunction was a powerful magical helmet that was capable of breaking any 'enchantment' within its vicinity. It was a highly sought-after artifact by groups across the Realms, from gnomes of the Underdark, to the Cult of the Dragon, and adventurers from the Sword Coast North.

Description
It was a sleek, golden, open-faced helm with ridged and dimpled patterns. A design over the brow displayed two draconic figures rampant and flanking a symbol comprising three circles: one small, one large, and one small, arranged vertically. Two diamond-shaped emeralds were set above and below these.

Powers
The helmet of disjunction required attunement and its powers could only be commanded by a mage, whether a wizard, a sorcerer, or a warlock.

With the helmet of disjunction upon their head, the mage could use to emit a powerful pulse of antimagic up to away in all directions. This was capable of disabling all magical enchantments even partly within the area, destroying magical scrolls and potions, ending active spells, and suppressing magic items for 1 minute, thus shutting down everything from driftglobes to the powerful Mordenkainen's arcane seal. It appeared to replicate the effect of the spell known as Mordenkainen's disjunction. The user themself was protected, with their own magic items unaffected. Artifacts were also not harmed by the effect.

Alongside this pulse was a wave of force that could knock over all creatures within a range of away.

It could be used once, and then not again for one to four days afterward.

History
It was first created by the wizard Mordenkainen of Oerth; it's unknown if he ever made more than one. In any case, he later wanted nothing to do with that "accursed thing".

The Battle of the Evermoors
"The Tribe of the Elk and the Cult of the Dragon clashed, antlers against fangs, over a mythic artifact capable of breaking any enchantment: the helmet of disjunction."

- Xenk Yendar, beginning the story of his time with the artifact.

Sometime around 1400 DR, the helmet of disjunction was in the possession of the Elk tribe chief, Stanhard Grimwulf, but desired by Rakor, the black dragon of the Evermoors who supported by the Cult of the Dragon. The two sides clashed in the ensuing Battle of the Evermoors. Although Stanhard's Elk warriors outnumbered the Dragon Cultists, Rakor more than made up the difference by flying overhead and vomiting acid on the barbarians' ranks. Badly pressed, Stanhard gave the helmet of disjunction to one of his men, Toke Horgath, to carry to safety, but Toke was abruptly cut in half by a Dragon Cultist. Ordering a retreat, Stanhard retrieved the helmet and entrusted it to his fastest rider, Ven Salafin, to get it away from Rakor however he could, before the chief was killed as well.

But as Ven fled the field of battle with the helmet of disjunction, he was injured and lost his horse. He was forced to crawl to safety, then collapsed, and lay dying. At last, he was met by the heroic Thayan paladin Xenk Yendar, who inspected his wounds but could not help him, and promised to protect the Helmet. Believing him, Ven gave up the helm and expired.

Quest to Secure the Helm
"Forthwith, I set of on a quest to secure the helmet of disjunction a home for safekeeping. Though I soon realized that everyone I approached either wanted nothing to do with it... or they wanted it for the wrong reason."

- Xenk Yendar, continuing his tale.

Xenk then set out on his quest to secure the helm, keeping it safe from those with nefarious intent. He rode atop his steed to locales across the Realms; he visited the mage tower of Mordenkainen himself during one of his trips to Waterdeep, who wanted it nowhere near him for fear it would destroy everything magical he owned, and was forced to fight off renewed attempts by the Dragon Cult to steal the helm back.

Eventually, Xenk took the helmet of disjunction into the Underdark, to a region near the ruined deep gnome city of Dolblunde. There, Xenk encountered two sisters, Trick and Trap, who first tried to trick the stalwart paladin, but then appealed to his sense of honor and justice. The sisters sought the helmet to save their fellow gnomes, who had been subjugated by the elder brain Zuphelithid.

And so Xenk Yendar took on the liberation of the gnome people as his next quest. He and the gnome sisters worked together to slay the terrible elder brain and free the enslaved gnome people. In gratitude for all he had done, Trick and her people created a safehouse for the helm of disjunction within the ruins of Dolblunde. In the part of the city suspended over lava, they placed it inside a gnomish mechanical box and rigged the bridges to collapse if not traversed in an intricate sequence only known to, and understood by, Xenk Yendar. Xenk believed it would be safe here, because it was "the last place anyone who values their life would go."

Retrieval From Dolblunde
"Perhaps one day new heroes will rise to the challenge of its protection. I hope they are worthy of it. They have tiny but tenacious shoes to fill."

- Xenk Yendar, after having succeeded with his quest to secure the helm.

There it would rest for a hundred years or so, until, in the late 1490s DR, a band of thieves consisting of Edgin Darvis, Simon Aumar, Doric, and Holga Kilgore—a warrior of the Elk tribe who remembered her tribe's role in the battle—went in search of it to aid them in cracking the Mordenkainen's arcane seal securing the treasure vault of Castle Never in Neverwinter. They exhumed the bodies of fallen Elk tribe warriors at the Evermoors cemetery and used Simon's deathly token to speak with the dead in order to learn the fate of the helmet of disjunction. The eternal rest of the helmet's bearers and others were all disturbed for the sake of a few questions, mistaken identities, and misused spellcasting.

They went to Mornbryn's Shield to ask Xenk about the fate of the helmet of disjunction and gained his assistance by speaking of their desire to rob and bring down the corrupt and tyrannical Lord Forge Fitzwilliam of Neverwinter and of his connection to a Red Wizard of Thay, Sofina, and by promising to share any stolen riches with the Neverwintan people.

Venturing down into the Underdark, the party arrived at the ruins of Dolblunde. After negotiating the trapped collapsing bridges, that is triggering and collapsing them before Xenk could finish explaining the intricately complicated technique needed to cross them, Simon used a hither-thither staff to cross into the city. Finding and opening the gnomish mechanical box, Xenk retrieved the helm and entrusted it to Edgin, who passed it to Simon. After battling and escaping undead Thayan assassins and the red dragon Themberchaud, they escaped the ruins of Dolblunde with their lives and with the helmet of disjunction.

Some time later, they emerged in the Sea of Swords and swam to shore, where they rested on the rocky beach. However, the hard part still lay ahead of them—Simon Aumar would need to attune to the helmet of disjunction, something he had a hard time doing. Each time he donned the helm, he was confronted with a vision of the ethereal plane and of his illustrious ancestor, the great mage Elminster Aumar, which would dismiss Simon's efforts and end the process, knocking him over and sending the helm flying off his head. Eventually, Simon feared he could never attune with it.

Ultimately, though, in the heat of the moment of trying to break the Mordenkainen's arcane seal on Castle Never's treasure vault, and pursued by the Neverwinter Guard, Simon tried the helmet again. This time, he confronted the vision of Elminster, finding it to be nothing more than himself holding him back. He successfully used the helmet of disjunction, bowling over the guards, opening the vault, dropping driftglobes, and obliterating magic across a swath of the city, as well as making him feel better about himself.