The Eldrazi are an ancient race native to the Blind Eternities that have neither physical form nor color alignment. Their nature is ceaseless hunger, so they travel between planes devouring the mana and life energy until the plane’s destruction. Three Eldrazi titans were bound on Zendikar in aeons past: Emrakul, Ulamog, and Kozilek. Emrakul warps biology, Ulamog warps physical properties and Kozilek warps reality.

«We shall forever roam».
– Ayil, High Priest of the Eternal Pilgrims

It is unknown whether more titans exist elsewhere in the multiverse. Each titan lives outside of the planes. When one wants to feed, it extends a part of its «body» into the plane, to create a physical manifestation of itself there, as well as an army of drones that are extensions of its body and will.

The spirit dragon Ugin compared this to a man sticking his hand into a pool of water; the man being the Eldrazi titan and the water a plane. The fish —those who dwell on the plane— see only a part of the man: his hand. Likewise, the inhabitants of a plane can see only a part of each titan. Even if the lesser Eldrazi appear to be independent beings, their physical forms are just part of a greater entity outside the plane; they are all just part of the titan that made them.

While the plan to eliminate them worked at first, once the Eldrazi titans were anchored to Zendikar, their destructive essence threatened to assimilate Zendikar into themselves. Chandra, a pyromancer, and Nissa, an animist, channeled their magic through Zendikar’s leylines directly into the titans. In one brilliant stroke of flame, Ulamog and Kozilek were incinerated and destroyed, leaving only ashes raining from Zendikar’s sky. Even though Ugin considered the two titans destroyed, it is unknown whether the flames truly destroyed the two titans or solely their planar avatars. Meanwhile, Emrakul has left the plane for destinations unknown. Later, she arrived on Innistrad after being summoned there by Nahiri to take revenge on Sorin. After wreaking havoc and corrupting a large part of the plane, she allowed herself to be imprisoned into Innistrad’s moon for an unknown purpose.

Though each lineage has distinct anatomy, each of them seems to have a commonality. Each has a proboscis located somewhere near a joint that acts as a feeding tube, attaching to a subject and draining them of life. Eldrazi proper and their infant spawns have no color alignment and the mere presence of larger Eldrazi can cause reality to dissipate. However, Eldrazi drones born to serve the larger base species are often aligned, being few examples of the creatures that are colored. Eldrazi drones, while formidable, are not as powerful as their larger counterparts and do not have the Annihilator ability.

• The progeny of Ulamog are characterized by having a bony mask over their heads, being completely featureless. They also possess writhing tentacles in addition to their aforementioned bisecting arms.
• The lineage of Emrakul are perhaps the most bizarre of the Eldrazi, possessing a strange lattice-like flesh composition and being of unnatural hues (predominately of bright purples, blues, and reds). Like the lineage of Ulamog, many possess tentacles seemingly for no real purpose. They have no discernible sensory organs and many do not possess conventional forms.
• Those born from the lineage of Kozilek have multiple eyes all over their body (curiously, rarely on the head) and have large, black jagged plates that float around them. They are also characterized by bisecting arms which they share with the Ulamog lineage.

The idea of the Eldrazi as timeless alien gods worshiped by ancient cultures bears similarity to the mythos of H.P. Lovecraft, which included extraterrestrial «gods» that would potentially destroy the realm of humanity, and warp time and space as they enter this universe.

In Dungeons & Dragons

Introduced in Tasha’s Cauldron of Everything, supernatural locations are permeated by a preternatural force in an area. In such an area, certain effects and brief encounters reinforce an underlying theme. In this case, the Forsaken Monument is actually the remains of an Eldrazi, and its influence is still felt in the area, warping living beings into twisted versions of them.

Some small modifications to existing monster statistics can make creatures feel more like the Eldrazi that are consuming Zendikar. If a creature enters the area of effect of the Forsaken Monument, roll 1d6 and determine what additions and changes affect it:

1. It becomes immune to psychic damage.
2. It becomes immune to the charmed condition.
3. Its eyes get blank; it is immune to the blinded condition and has blindsight to a range of 30 feet.
4. Its damage for natural attacks change to necrotic damage.
5. It gets the «Eldrazi spawn» trait: if a creature with the type Eldrazi is within 5 feet of it, this can consume it to transfer hit points from it and regaining the use of a single ability as though it had finished a long rest if it transfered more than 20 hit points.
6. Roll twice (and so on if rolled again).

An additional option is to have the area of effect in phases. For example, if the total area is 120 feet, if the creature enters the outer area of 30 it gets one addition, but if it gets into the innermost one, it gets three.

In Eberron

When placing the eldrazi into Eberron context for one of my campaigns, I decided to do it in the depths of Xen’drik, and implanting them as a sub-species of the Quori, one more related to the plane of Xoriat than to Dal Quor.

How are you planning to face the aberrant Eldrazi? Will you venture into the deeps of the wastelands to destroy once and for all to the last bastion of their influence?