The Precursors

Summary
The Precursors are a primordial race of godlike beings that have thrived for billions of years. They traveled across galaxies, spread life throughout the universe, and oversaw the evolution of life in many of the galaxies of the universe.

They were the most advanced known race in the Halo-verse with technology that transcends normal comprehension and physical limitations. Their Neural Physics based technology was based around the idea of the universe itself being a living and sentient entity but in a manner far beyond the comprehension of normal beings. They could create nearly indestructible mechanisms which could survive supernovae and in the cores of stars. Their structures could be thought of as living entities themselves (they could change mass and shape at will and even act as weapons to attack other constructs).

Powers and Stats
Tier: At least 2-A

Name: The Precursors

Origin: Halo

Gender: Genderless

Age: Over one hundred billion of years

Powers and Abilities: Superhuman Physical Characteristics, Evolution Manipulation (Influenced the course of Evulotion and can easily devolve beings), Information Manipulation (Contraons and maintains the data of The Past within "The Domain"), Reality Warping & Creation (Shaped several Galaxies and Constellations within The Universe), Pocket Dimension Manipulation (Controls slipspace, an entire pocket dimension), Telepathy (Can telepathically communicate with beings across The Universe), Technology Manipulation (Hacked various advanced AI's and completely changed their programming), Space-Time Manipulation (Dictates the course of Space-Time and can casually manipulate both Time and Space), Non-Corpreal (Exists without a physical form and can live freely without physical bodies), Shapeshifting (Can alter the apperance of their physical bodies), Immortality (Type 1 & 3), Regeneratiom (Low-Godly, Can survive as merely a concious without a physical body), ETC.

Attack Potency: At least Multiverse Level+ (Surpasses the technology of The Forerunners, who can harvest an infinite number of universes as a means of generating power to sustain their homes. Possibly manipulates the higher dimensions within The Halo Multiverse)

Speed: Massively FTL+ (Far superior to slipspace travel, the fastest of travelers can reach speeds billions times faster than the speed of light, can traverse the galaxy in a matter of seconds), Possibly Immeasurable (Implied to inhabit a space higher than the 3rd Dimension and exists as incomprehensible entities)

Lifting Strength: Unknown

Striking Strength: Multiversal+ (Forerunner techology is a weak compared to even the most basic of Precursor tech)

Durability: Unknown. Regeneration and Non-Corporeality makes them harder to kill

Stamina: Limitless 

Range: Galactic

Holdings: Many galaxies, they exist and manipulate multiple other dimensions

Standard Equipment/Holdings/Technology:

Neural Physics: Neural Physics is a Precursor technology that draws from an exotic neurophysical energy that permeates the cosmos. Creations made through this sort of technology are effectively indestructible, allowing them to exist for millions to possibly billions of years without any sign of decay. As such, this evidence of the Precursors' mastery of neural physics remained long after their disappearance, within the form of star roads, and many other vast structures.

In the final years of the Forerunners' war with the Flood, the proliferation of Keyminds ascended them to an intellect sufficient to reach trans-sentience, which enabled them to use their vast mental capacity to utilize the architecture. With that, the Flood also began to use Neural Physics based Precursor superluminal travel, which rendered the Forerunners' method of slipspace unsuitable on an interstellar scale. The form of FTL travel that the Precursors used was a form of causality compensation that was unlike the reconciliation that the Forerunners relied on. However, ships using this form of FTL travel would shed multiverse residues relatively slowly upon returning to normal space, rendering them momentarily vulnerable.

Star Roads: Also known as Unbending Filaments, these neural physics based constructs were seemingly inert, several kilometers thick, and virtually unbreakable cables that lay across the galaxy for millions of years, even after the Precursors had disappeared. On a smaller scale on some worlds, these star roads formed orbital and suborbital structures like orbital arches. On a larger scale, however, Star Roads were used to connect and link planets and even entire star systems to one another. Like other Precursor technology, Star Roads are not made of conventional matter, instead of being composed of Neural Physics construction that is capable of changing it's mass at will.

During the Final Years of the Flood's war with the Forerunners, Keyminds were able to use these constructs as a weapon, being capable of tearing apart whole Forerunner fleets and astronomical bodies (to the point of destroying entire solar systems), actively hindering Forerunner Slipspace travel, as well as generating suppression fields to disable Forerunner technology. These Star Roads were able to move across interstellar distances by way of using the Precursors' method of Slipspace travel and said structures warped the reality around them, mutating spacetime and caused Slipspace to be unusable for Forerunner transit.

Intelligence: Immense, they were the only civilization on the Forerunner Technological Advancement Scale to be ranked as "Transsentient", putting their technological prowess above that of the Forerunners and Ancient Humanity.

Weaknesses: Spiteful and rather arrogant. Their military might not have been all that powerful considering a less advanced race successfully carried out a genocide of them, although according to the Primordial, they let themselves be killed in awe of the Forerunners' violence.