Angels

Angels are a group of luminous and heavenly beings in the lore of Dota 2.

Abode
Some angels like Lucifer before his fall dwell in a heavenly place known only as the “the realm behind the light”, “the light”, or “Paradise” which is Dota 2's version of Heaven.

One angel known as the Omniscience dwells in the earth's deepest core as a result of it allegedly creating the mineral shell around it that became the planet of Dota 2.

Characteristics
Like most things in Dota 2's lore's soft worldbuilding, angels are very loosely defined beings. But based on the few mentions of them in the lore, it may be said that they are holy beings of light who bear wings that keep them bound to the light and prevent them from falling away.

Culture
Defiance to an unknown entity or covenant is a sin among the Angels, which is punishable by exile. The angel's name is tolled from the forged steel bell of Vashundol, forecasting their punishment via branding their wings with fire until they are reduced to stumps, releasing the wingless angel from the realm behind the light and banishing them forever.

Speculation
The lore of the, the Light Brigade, Light's Keep, and the Light itself whence Ezalor rides from might be connected to the lore surrounding the angels.

First of all, the many meanings of Lucifer's name are related to light, with meanings like "light bringer" or "morning star" being a few examples. So he was once holy and luminous.

The Light Brigade is implied to be the Light's army, whereas Light's Keep is an aptly named place where the Light is presumably kept. Perhaps connections can be drawn to the angelic army that Lucifer once led before his fall as a favored general and the realm he was exiled from to the luminous brigade and keep respectively.

What truly connects this Brigade and this Keep with Lucifer's implied army and the place behind the light is the one similarity he has with Ezalor: a rebellious temperament. Lucifer defied his mysterious father by refusing to kneel just as the headstrong Ezalor escaped the Fundamental Plane in defiance of the “first covenant” that he still defies today.

It's possible that Lucifer inherited Ezalor's rebellious nature as his descendant at the very least, which means that the latter once led the angels and their general Lucifer as well. Hence Lucifer and the angels may also serve the same light that the Keeper himself keeps safe.

Heroes
was once a favored angel general from the realm behind the light, until he fell from grace for his defiance and was stripped of his wings, banishing him from Paradise.
 * Even after his exile, Lucifer still lives up to his name as he bears a flaming sword (like an angel's) so bright that it consumes the darkness.
 * Although he is no longer among his former holy kin, Lucifer still believes that he is peerless among the angels.

Gods
The Omniscience is a of purity and light. It has wings that it casts upon those who implore its protection, delivering its faithful and their allies from harm.

is depicted as an angelic being in the. It has wings akin to an angel's and is seen in a place like Heaven with its clouds and sunshine.

Heroes
is very impressed by the unusual design of Doom's wings, even though very little remains of it.

claims to have not seen anyone or anything like Lucifer. Maybe he has never seen a fallen angel before, or there's something else to Lucifer that makes him unique.

can summon his to protect him and his friends from any physical harm by casting its loving embrace on them with its holy wings.

is disquieted by anyone who looks like an angel, such as with his feathered wings and light powers of divine and aetherial origin.

World
The prison plane Foulfell is a place where “angels fear to tread” according to Terrorblade, ignoring the reference to An Essay on Criticism by Alexander Pope.

Angels such as Lucifer are bound to the light in a place called “Paradise” or the “realm behind the light” by their pairs of wings.

Other
In the lore, there is something called Vashundol which has a steel bell that tolls the names of those who are about to be damned, such as insubordinate angels.