Black obelisk

The black obelisks were a series of magical artifacts originating from ancient Netheril that possessed various forms of incredible power, including the potential for time travel.

Description
The obelisks were said to be otherworldly in appearance, described as being formed from either obsidian, a polished rune-covered black stone, or a type of unidentified black metal. The monolithic devices were formed to gradually narrow from a wide base, to a pyramid-shaped peak in a range of different heights. Different obelisks were created in a variety of sizes, anywhere from  to even  and  tall.

At least in one instance, it was observed that any shard broken off from an obelisk would be somehow "absorbed" back into the whole by merely touching it to the surface.

Powers
The most notable and powerful power associated with the obelisks was the ability to alter time and reality. An individual could merely reverse the age of every nearby being by a decade's time, or even go so far as to transport an entire world thousands of years in the past within their timeline. Full activation of these powers required another powerful artifact with magical charges that seemingly had to be keyed into an obelisk, as was the instance with the staff of power belonging to the arcanist Iriolarthas.

The obelisks radiated auras of arcane energy, often in the form of abjuration magic. A spellcaster could readily tap into this energy to teleport themself and anyone else touching the device to a random location. These teleportation powers were known to have been linked to an "ebon pool" of black ooze and small, corresponding black marbles.

More than one obelisk was known to harbor a powerful extra-planar creature within its form, including a nalfeshnee, and even a couatl called Tezca-Zyanya.

They were seemingly unaffected by energies from the Far Realm, and were observed to illicit some form of reaction from the faerzress that permeated the caverns of the Underdark.

History
The predecessor of the Netherese obelisks were those created by an enigmatic group of spellcasters known as the Weavers. These were capable of altering time and reality on a grand scale, effectively working as a safeguard in the case a truly catastrophic event was brought upon their place of origin. At some point in time the Oerthian being Vecna procured one of these obelisks, along with the specifications of their creation, and used it to remove every other instance of the artifact from existence.

The information regarding the obelisks' creation eventually found its way to Netherese arcanists, who built the Faerûnian variety that could still be found millennia after their empire's demise. While the obelisks ultimately failed to save Netheril in the known world, several of them were stolen or otherwise recovered, and hidden away in remote locations throughout the Realms.

Some time after the, cloud giants from a floating castle stole the obelisk from its namesake town of Nightstone on the Sword Coast North, believing it to be a relic of ancient Ostoria.

Reputation
Knowledge of the obelisks, along with their function and creation were wholly lost to time on the planet of Toril.

Notable Obelisks
The obelisks known to have appeared throughout the Realms included those in the following locations:


 * Nightstone, the great megalith was the landmark around which the walled town was built.
 * Shadowdusk Hold, an intact obelisk was recovered in Undermountain by the disgraced Shadowdusk family and later held within their subterranean domain.
 * Tomb of the Nine Gods, a moss-covered obelisk defaced by the lich Acererak marked the entrance to the deadly dungeon in Chult.
 * Whorlstone Tunnels, one broken obelisk could be found in the labyrinthine tunnels beneath Gracklstugh in the Underdark.
 * Ythryn, one fully-functioning obelisk remained embedded within the ground of the fallen enclave Ythryn, stuck deep beneath the ice of the Reghed Glacier.

Appearances

 * Adventures
 * Out of the Abyss • Tomb of Annihilation • Waterdeep: Dungeon of the Mad Mage • Icewind Dale: Rime of the Frostmaiden