If You Build It They Will Play: Hedrons

I started playing Magic: the Gathering with the Antiquities set...so 1994, I guess? I've always found many of the game's Planes fairly interesting and Zendikar is among them. In the setting, a geomancer, created these floating monoliths or Hedrons, to imprison the game's riff on the Great Old Ones known as the Eldrazi.

Since the Craglands have been dealing with the threat of expansion of the Far Realms I decided to use the Eldrazi as a change of pace.

The Hedron appears, passing through a newly formed Rift, moments after an unexplained explosion within a nearby mine and immediately begins floating at about 15' in the air where it remains stationary and vibrates at a frequency that is just barely audible (DC 13 Wisdom (Perception) check).

The Rift, which appears as a night-black oval set into the ground, is a slightly larger than an average human and is 15° cooler than the rest of its environment. Looking directly into the Rift requires a DC 12 Wisdom Saving Throw which causes a level of Exhaustion on a failed roll.

Anyone who succeeds on a DC 12 Intelligence (Arcana) check knows what the Hedrons are and that they are rare on this Plane. If the total is a 15 or higher then it is known that the Mage King Suleiman III of Khersia wrote that our Plane and Zendikar's were somehow linked during the sinking of Hem-Hoomod, the Ivory Seat of the Woodeel Empire, which marked the end of the 7th Age and the beginning of our current one. With a total of 18 or higher it is know that Ur-Hukar, the High Vizier to the Ivory Seat, came upon the Invector Prima, a foul tome devoted to the Higher Ungods, the name of the Eldrazi during the 7th Age, which corrupted him body, mind, and soul. If the total is 20 or higher then it is know that that Hussars of Vim use a strange form of magic to detect, track down, and destroy Hedrons and then cleanse the area via the Meteor Swarm spell.