Hedron

Hedrons are ancient stone monoliths found throughout the plane of Zendikar. When properly aligned, hedrons become powerful tools of binding.

Origins
It was revealed that Nahiri constructed the hedrons during a period of 40 years, forming a Hedron Matrix connected by leylines that created a planewide prison for the Eldrazi. Ugin guided Nahiri in shaping the surfaces of the hedrons. The carved stones devices were created to both condense mana and strengthen the containment spell which held the Eldrazi in their prison, but ultimately had very undesirable effects on the plane. They hold an incredible amount of power inside, but it takes a powerful mind to open them. The runes featured on the Dragon Scroll, known to be written in draconic language, are carved on a hedron inside of the Eye of Ugin.

Secondary use
The alliance of hedron creatures like Hedron Crawler, Hedron Scrabbler and Runed Servitor can be assumed as guardians of the hedron network.

Chips broken from hedrons would be used as Pathway Stones in Tazeem, directional tools that always led to the center of hedron fields. This regionally anomalous property may be attributed to Emeria, the Sky Ruin, a unique collection of hedrons and stone rubble floating over areas of Tazeem. Additionally, the Onduan settlement of Kabira innocently mimicked nearby hedron runes and shapes in architecture, an act which scholars of Kabira Conservatory believe endangers residents.

Using the shard of a shattered hedron, Sarkhan was able to protect Ugin after his fateful battle with Nicol Bolas.

Reboot
Since the Rise of the Eldrazi, the dead stones began forming bizarre floating superstructures in the sky. Some hedrons had been transformed, taking angles and shapes unique to that of their first construction.

When Ulamog threatened to destroy the plane, the Planeswalkers responded. While Gideon Jura's troops and Kiora's forces held the city against the assault, Nissa Revane used elemental power to raise sunken hedrons from the ground and position them into Aligned Hedron Network. Jace Beleren activated the hedrons, thus trapping Ulamog. Following the events, the network was then undone by Ob Nixilis.