Cycle of Strife

"Standing in the ancient city of Corvus, Daedessa the Builder bestowed the Eternal Crown on her son, Kion. Fueled by the artifact's power, Kion formed the Immortals. And swore to protect Sanctuary from the Burning Hells. But he would not do so unwatched. Knowing that power corrupts, Daedessa charged her daughter, Akeba, with a heavy burden. It would be her job to ensure the Immortals were forever worthy of this gift. Should they ever fall to the Burning Hells, Akeba and her Shadows would take their place as the defenders of Sanctuary."

- Anonymous

The Cycle of Strife is the never-ending battle between the Immortals and Shadows.

Lore
"Once more, the Cycle of Strife ends in blood. And the power of eternity rests in new hands. The old order, and all its tainted glory, shall fade into history. While the victor assumes the crown's gifts, and its burdens. Thus the Immortals are born anew, and the wheel turns again. Will this new light resist the shadow once more? Must the Cycle of Strife end in blood?"

- Anonymous

The seeds of the Cycle of Strife lie with the formation of both groups. Per the orders of Daedessa, the Immortals were formed to guard Sanctuary against demonic threats, while the Shadows were formed to constantly test the Immortals. It was agreed that if the Shadows ever defeated the Immortals, they would become Immortals themselves. This came to pass, with Akeba becoming the next Immortal. However, not willing to rest on her laurels, she founded the Cycle of Strife, which has continued ever since, with the Rite of Exile reguarly being conducted, and beyond that, the Challenge of the Immortal.

The Cycle of Strife was still ongoing by the year 1270, though was escalating by this point.

Gameplay
The Cycle of Strife is a game mechanic of Diablo Immortal. It is based on clans competing with one another. Each clan has the ability to become a "dark clan." If a Shadows clan defeats the Immortals in the Rite of Exile, the current Cycle ends, and a new Cycle begins. At that time, everything connected to the current Cycle resets. This includes all ranks, Eternal Crown levels, Path of Blood progress, and so on. Additionally, when a Cycle ends, participating heroes earn Deeds of Valor, special titles connected to their performance that Cycle. The former Immortal and their lieutenants will be engraved on the Wall of Honor, as a permanent place of remembrance to reflect on that group’s reign.

If the Immortals successfully defeat the Shadows, the Cycle continues as normal.

Development
The Cycle of Strife initially functioned differently. There would only ever be one group of Immortals on a server, with up to 500 members. There was no limit as to how many Shadows could be active, and they would all be vying to displace the current group of Immortals. The Cycle was expected to reset each month.

Players could originally form Dark Houses. This was replaced by the "dark clan" system.

Trivia

 * 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 (and therefore, the Shadows) were formed and/or were active well after the Sin War. This would place the implementation of the Cycle of Strife as being a relatively recent development in Sanctuary's history.