Infinite Forest

"An infinity of possible worlds, so perfectly simulated as to be indistinguishable from the experiences I once called “reality.” I can touch them, taste them, pass lifetimes in them! They grow within this machine like fruit upon a tree — no, a forest of trees, its fractal expansion nigh unmeasurable. (...) What an awful, destructive machine this is. I must know everything about it."

- Osiris

The Infinite Forest is a location accessible through a gateway in the Fields of Glass, Mercury. It is a Vex virtual realm within the Nexus that are infinite Realistic simulations of the universe which the Vex plan their actions out in reality. The Vex hollowed out Mercury's core and in its place built the mechanism that generates the Forest. It was overseen by Panoptes, Infinite Mind until its destruction. Simulated versions of Dendron, Root Mind created by Osiris have attempted to take control of the Forest, but have been destroyed by The Guardian before they could assume the role.

Overview
The initial area of the Infinite Forest, the interior of Mercury's core, contains four tower-like structures with gateways, three of which lead to different time periods within different simulations, and one that leads back to Mercury's surface. The sleek, futuristic tower to the left of the entrance leads to the distant past where Mercury is a lush jungle; the tower directly across the entrance, which is comprised of conventional Vex architecture, leads to iterations of the present; and the crumbling, darkened tower to the right of the entrance leads to the far future, where the Sun is long dead, along with all life and the Vex have spread everywhere. As Guardians move toward the main towers, they encounter simulated Cabal, Fallen, and Hive, as well as Vex, and must defeat the disguised units called "Daemons" to generate new pathways and advance, these pathways change randomly everytime one enters the forest. And just like on Nessus, Time moves differently between inside the Infinite Forest and outside, when exiting the forest is when you just entered. The one enemy race that does not appear in simulations are the Taken.

Within the actual simulations of the past, present, and future, Guardians will continue to encounter simulated enemies from the other races. For example, in one of the infinite variations of reality being analyzed, the far future where the Vex have triumphed over everything may also contain Fallen survivors. The Forest can even simulate realities where the Infinite Forest did not even exist.

Though the Forest is infinite in so many ways, they also pertain to victims trapped there for infinite eternities as Well. Also the geometric data of the Forest’s architecture subtle shifts with reality trying to decide what version it wants, and time is constantly in flux as well

The Golden Age
The construction of the Infinite Forest engine began during the Golden Age, while Mercury was still a garden world and the Vex had only recently arrived. The algorithm used to generate the Forest was housed within the Gardener's Spire, overseen by Dendron, Root Mind. Panoptes, Infinite Mind was tasked with managing and interpreting the Infinite Forest's simulations to inform the Vex's strategies in the "real" universe.

City Age
Following his defeat of Solkis, Devil Kell, Saint-14 received word that Osiris had ventured to Mercury to investigate the Vex's activities. Fearing that the exiled Warlock would instigate a full-blown war with the Vex, Saint-14 followed Osiris to Mercury and went looking for him in the Infinite Forest. He battled a horde of Vex within the Forest, and was eventually confronted by a Vex Mind specifically designed to drain his Light. Though Saint vanquished the Mind, he succumbed to his wounds and died his final death; the Vex constructed a tomb for him within the simulation, seemingly as a gesture of respect.

Curse of Osiris
After the Traveler released a pulse of Light at the conclusion of the Red War, the gateway to the Infinite Forest reactivated.

Forsaken
While the City celebrated the Festival of the Lost in the year after the Red War, the Infinite Forest began exhibiting strange behavior, with the primary simulation area within Mercury's core becoming darkened and inhabited by simulated entities known as "Nightmares". Later, A part of the Forest started to exhibits an environment of lush, greenery during the Revelry Event.

List of appearances

 * Destiny 2
 * Curse of Osiris

Trivia

 * It is also mentioned during the Tree of Probabilities Strike that on the off chance, simulations of the Cabal could escape the Forest with world ending tech. And another transcript that they can escape where they succeed in obtaining Vex Tech. This would imply that Simulations can enter the physical universe.