"The Immortals. Bestowed with righteous power by Daedessa the Builder. Their charge? To defend Sanctuary against the Burning Hells. To use their strength to keep the relentless demons at bay. To be a beacon of hope and light. But victories are temporary, and the Immortals can never relent or yield. Even if all hope seems lost, they must find the courage to stand defiant for all time."
— Faction description(src)
The Immortals are a guardian order of Sanctuary.
Lore

Adventurers behold the Immortals
The Immortals are "the most elite heroes" of the mortal realm.[1] They keep their spoils inside a vault,[2] which includes a plenthora of tools that aid them in their eternal watch over Sanctuary.[1]
A single Immortal who bears the Eternal Crown leads the Immortals. The leader is accompanied by four lieutenants with crowns of their own. If an Immortal falls, their name and those of their four lieutenants are engraved on the Wall of Honor.[1]
History

The Immortals in battle
Long ago, the nephalem Daedessa bid her son, Kion, form a group whose sole purpose would be the protection of Sanctuary from the Burning Hells. Kion obliged, and created the Immortals. In secret however, she bid her daughter, Akeba, to form a group that would constantly test the Immortals. Akeba called this group the Shadows, and they constantly tested the Immortals. It was agreed that should the Shadows ever overthrow the current reign, they would take possession of the Eternal Crown and become the new Immortals.[2]

The Shadows attack the Immortals
For a time, the Immortals successfully kept the demons of Hell at bay.[3] However, events went awry for the Immortals when they battled against a force of demons in a forest, led by Rakanoth.[4] The outcome of this battle is unclear, but it appears that it did not go in the Immortals' favor. Whatever the case, it was after this that the Shadows moved against the Immortals.[5] The Shadows emerged triumphant, with Akeba becoming the next Immortal. She began the Cycle of Strife, which ensured that the Shadows would always test the Immortals, beginning a state of affairs that lasted well into recent times.[2]
Gameplay
Players can function as Immortals in Diablo Immortal; this is an entirely opt-in feature.[2] There can only be up to 300 Immortals[6] on a server. Shadows, of which there are an unlimited number, are constantly trying to displace the current group of Immortals. Once the Shadows reach a certain point in their progression, the Rite of Exile event is triggered.[2] Beyond this, a player will be transformed into an Immortal boss in the Challenge of the Immortal event, where they will gain a massive power buff and unique abilities.[7]
If a Shadows Dark Clan beats the other Dark Clans and overthrows the Immortals, then that winning Dark Clan will become the Immortal Clan. Players in an Immortal Clan will stay together as a unit and can invite up to two other Dark Clans to become Immortal Allied Clans. When the Immortals’ reign ends, as all reigns must, the Immortal Clan will return to being a normal Clan as the Cycle begins anew.[8]

The Immortal and their four lieutenants
A single Immortal leader bears the Eternal Crown, and four lieutenants have crowns of their own. Each crown grants an extraordinary power once it has reached a certain level of progression thanks to the reign's Dominance. A mixture of offensive and defensive buffs will emanate from these Legendary items, amplifying the wearer’s might as well as that of other Immortals in close proximity.[1]
Immortals have exclusive access to the Kion's Ordeal event, and can take part in the Raid the Vault event.[2] As Immortals complete tasks (I.e., Daily Goals) the Immortals will accumulate Essentia, a resource to spend which enables attempts on raids like Kion’s Ordeal.[1] The Immortals also have access to the Corvus Expedition.[9]
Trivia

Immortals battle demons (khazra included)
- Khazra appear in the Cycle of Strife trailer for Diablo Immortal, showing ancient nephalem Immortals battling khazra and other demons. This is either an error (as the khazra were formed after the Mage Clan Wars), or indicative that the original group of Immortals were formed and/or were active well after the Sin War.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 2021-04-21, DIABLO IMMORTAL CLOSED ALPHA — THE CRUSADE BEGINS. Blizzard Entertainment, accessed on 2022-05-25
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2021-04-22, Diablo Immortal's Team-Based PVP Endgame Cycle of Strife Revealed. IGN, accessed on 2021-06-16
- ↑ 2021-12-03, Cycle of Strife | Immortals. YouTube, accessed on 2022-05-26
- ↑ 2021-12-03, Cycle of Strife | Introduction. YouTube, accessed on 2022-05-10
- ↑ 2021-12-03, Cycle of Strife | Shadows. YouTube, accessed on 2022-05-10
- ↑ 2022-04-05, DIABLO IMMORTAL INTERVIEW AT MEINMMO (GERMAN). Blizzplanet, accessed on 2022-04-16
- ↑ 2021-10-29, Diablo Immortal's Closed Beta Launches Today... Complete With Controller Support. IGN, accessed on 2021-11-07
- ↑ 2022-02-23, DIABLO IMMORTAL: CLOSED BETA LEARNINGS. Blizzard Entertainment, accessed on 2022-03-30
- ↑ 2022-05-24, DIABLO IMMORTAL PRE-LAUNCH PRESS EVENT ROUNDUP. Blizzplanet, accessed on 2022-05-27