Elemental Plane

The elemental plane (also known as the elemental realm or elemental force) is a plane of existence in the lore of Dota 2.

Description
Existing far beyond our material world which is a shadow of this plane, the greater elemental plane is the domain of the elements and the elementals' home.

The elemental plane is possibly implied to exist between the planes, since Barathrum (who hails from this plane) says he is from the interstitial space between the planes. If so, then this plane generates a damaging friction on the physical forms of those who slide into this realm. Spirits lost in this plane eventually become minerals to be mined and forged.

Heroes
As an ice elemental, it's implied the truly comes from the elemental plane, since she is advantaged against her enemies there. One of the reasons why she has participated in the war of the Ancients is to simply win the fight, lest her defeat threaten the elemental plane with doom. Piling more mystery and doubt on 's true identity is his status as an elemental who returns to the “elemental force” when he dies to reform himself.

According to Barathrum, is a fellow walker between the planes. But this may be a reference to the planeswalker Leshrac from the Magic: the Gathering card game. hails from the elemental realm. Just like the Conduit of Blueheart, he has joined the Ancients' war for the sake of achieving victory, as defeat will have repercussions in his home plane. The ring on his bovine form's nose is a symbol that the material plane he works in is a shadow of the real plane that is his home.
 * Since it is his home realm, death will send him back here before he reincarnates and returns to our world, but sometimes he may be lost on his way back for a moment. When he wins the Ancient's war, he will mention an open golden door between the planes, perhaps a way back to his home as a reward. However, if he loses, he will be lost between the planes.
 * Barathrum delivers his ultimate by sliding back into his home realm between the planes before reappearing next to his enemy to strike them with the retribution of both his realm and its shadow. The spell calls the plane he returns to the “nether realm” for some reason, perhaps referring to the fact that this place is an afterlife since the souls of those he has slain will depart to here or just the word “nether realm” being used for any spiritual plane of existence.
 * Barathrum can turn his form invisible by walking between the planes, imperceptible to anyone who isn't on his plane of existence.
 * Barathrum owns some equipment related to his home realm. Among them is a magnetic helm that was hewn upon an elemental forge and a flail that was forged around a core of compact elemental energy. When prying open the rifts between worlds, he draws the strength to do so from a pair of heavy gauntlets. He's also protected from the damaging friction generated upon his physical form when sliding between the worlds by his heavy pauldrons.

Heroes
Such is the heat of the 's resolve that it combines the elemental and terrene planes into one, presumably allowing him to manipulate the fire element.

World
The lesser terrene plane is just a shadow of the real world that is the elemental realm.

Events
Those of the elemental plane seek victory and success in the war of the Ancients, for defeat in this battle causes unpleasant repercussions in their home.