Lithos

The Gateway, a Lithos situated on Genesis.

The Lithos is a term designated by human researchers to refer to a series of Forerunner access nodes situated across the Milky Way galaxy, designed to allow for access to the Domain. They are present on numerous worlds and megastructures both natural and artificial. Many Lithos links and gateways existed throughout the galaxy, old terminals left on forgotten worlds, buried beneath bustling megacities.

Overview

The Lithos on Boundary.

Lithos sites serve as nodes that provide access to the Domain. During the era of the Forerunner Ecumene, they could be used to provide unlimited access to the vast knowledge reserves of the Forerunners.

After the New Phoenix Incident in 2557, the artificial intelligence Cortana was able to infiltrate and take over the Domain from the Gateway site located on Genesis. After this, access to the Domain became impossible except by way of an individual with an identical neural pattern to Cortana, such as a clone of Cortana's original brain donor Catherine Halsey. The clone could be used as a "key" to allow access to the domain. High Lord Dovo Nesto believed that accessing the Domain via a Lithos required the sacrifice of one's body - something he was prepared to do in order to become effectively an immortal god.

It is unclear how, or if, the Forerunners distinguish regular Lithos nodes and "gateways" like the one featured on Genesis. Under Project BOOKWORM, the United Nations Space Command keeps an eye on several such potential sites, they remain largely in the dark about the finer differences between them. During operations on Boundary, Tul 'Juran noted that the Boundary Lithos looked almost identical to the Genesis gateway.

The destruction of a Lithos released an immense amount of power. When the Lithos on Boundary was destroyed, thousands of nearby Banished and Covenant forces were killed in the strike while the Lithos burst into a pillar of light that tore into the sky. Several dozen ships in orbit were vaporized by the Lithos' destruction while others were severely damaged, either cast adrift or sent on a collision course with the planet's surface.

Worlds containing Lithos sites

Lithos sites are present across a number of worlds previously inhabited by the Forerunners. They are a common fixture on ice-worlds once used by the Lifeworkers to house vast rehabilitation complexes, and were used in the Forerunners' heyday to provide access to the empire's knowledge networks.

• Amasa
• Boundary (Boundary Lithos) - Located under the township of Tyrrhen
• Genesis (The Gateway) - Located in the coral highlands.
• Kamchatka
• Juvedai
• Strilun IV
• Zehar VI

History

Genesis gateway

The Forerunners constructed Lithos gateways across the galaxy prior to the firing of the Halo Array at the end of the Forerunner-Flood war. One such installation was hidden on the shield world of Genesis, nicknamed the Gateway. The Lithos on Genesis was hidden in the planet's coral highlands and rarely used, with the hope that the bioreadings in the region would hide its signature. This installation was used by Cortana to secure control of the Domain following her "death" aboard Mantle's Approach during the New Phoenix Incident in July 2557. During the process of taking control of the Domain, Cortana began to awaken Guardian Custodes across the galaxy and summon them to Genesis. She also began to awaken Lithos sites like the one on Kamchatka, which in turn drew the attention of both Jul 'Mdama's Covenant and the UNSC - culminating in a large battle there. Eventually, SPARTAN-II Blue Team were summoned to Genesis by Cortana and encouraged to enter the Gateway, with Cortana hoping to trap them in a Cryptum to keep them safe during her conquest of the galaxy. Covenant forces deployed on Genesis during the conflict there retrieved information about this gateway during their occupation of the site, and ultimately fed it back to High Lord Dovo Nesto of the Order of Restoration, who in turn began to plot about how he could use the Lithos to attain effective immortality in the Domain. Shortly after, Genesis was moved into a slipspace portal by Exuberant Witness, making its Lithos gateway inaccessible to the rest of the galaxy.

Exuberant Witness suggested that taking TDS-009 through the Gateway into the Domain would be the best chance for it to find peace, although the Monitor was unsure of how successful it would be with the Domain out of commission for so long and currently under Cortana's control.

After taking control of the Domain back from the Created, the Didact had the Haruspis seal the Gateway and all links to the Domain in the physical world so that no one could ever again abuse its power and resources as the Created had.

Hunt for the Boundary gateway

Chloe Hall and James Solomon in front of the Lithos on Boundary.

With the Genesis gateway inaccessible, High Lord Dovo Nesto, the leader of the Order of Restoration, instead turned his attention to finding another one of the Lithos' situated across the galaxy. On the shield world Cloister, he was able to acquire a tablet of Forerunner origin with Forerunner glyphs inscribed upon it; when analyzed and translated, these provided Nesto with the location of a new Lithos site - the human colony of Boundary. Nesto manipulated both War Chief Severan of the Banished and Sali 'Nyon, a remnant warlord who had recently rebelled against Jul 'Mdama, into assisting him with this plan, promising both the position of his right-hand once his godhood was attained. Thanks to information recovered from Reach, Nesto knew that the Domain could only be accessed by an individual with an identical neural pattern to Cortana - such as an identical clone of Cortana's original brain donor, Catherine Halsey. Knowing of the existence of such a clone, Chloe Hall, he counted on the UNSC's determination to stop him that would result in them bringing her to the Lithos site.

Information about the Lithos was first made available to the United Nations Space Command in 2559, thanks to the research team operating on Zeta Halo. Some time following Cortana's re-emergence on Zeta Halo, the research team were able to report back to UNSC command noting their knowledge of the Lithos as a series of Domain access nodes spread across the galaxy, similar in nature to the Kamchatka site. However, the team went silent shortly after, with the UNSC unable to ascertain if this information was discovered naturally on the ringworld or after the Created assumed command of the installation. This information was cross-referenced with a number of other Forerunner sites discovered by the Office of Naval Intelligence, though the locations of further Lithos access nodes remained unknown. However, with this information in hand, the UNSC began to look into ways of neutralizing the Domain to ensure that once Cortana was defeated,