The Traveler's origins are unknown. When it arrived, humanity first discovered it on Mars. It sparked a Golden Age of humanity that allowed humans to migrate from Earth to colonize other planets within the Solar System. Some speculate that the Traveler is a large vessel; others believe that it is a sentient being or artificial intelligence and some may even consider it a deity. As of yet its true nature is unknown.
The Traveler is credited with humanity's survival during the Collapse of the Golden Age. After the Traveler sacrificed itself to save humanity, it remained floating not far from the Earth's surface, and became silent and dormant. The City was built in its shadow and under its protection, where its inhabitants are temporarily safe from the threat of the Darkness.
The Red War
A year following the SIVA Crisis, Dominus Ghaul, leader of the Red Legion, attacked the City and trapped the Traveler inside a barrier, cutting off its Light from the Guardians. As the Red Legion occupied the City, they began constructing a cage around the Traveler for the purpose of extracting its Light to gain powers akin to its Guardians. Ghaul also captured the Speaker to question for how to be graced by the Traveler's Light, but the Speaker ultimately admitted that the Traveler never spoke to him before the Consul executed him. During Zavala's attack to retake the City, the Guardian came face-to-face with Ghaul aboard his command ship, where he was in the process of absorbing some of the Traveler's Light. Though the Guardian managed to kill Ghaul, he is resurrected as a massive ethereal figure of pure Light. As the Red Legion leader declared his apotheosis the dawning of a new age, the Traveler began to wake for the first time in centuries as it broke free of its cage and obliterated him, releasing a pulse that reaches throughout the entire galaxy.
Season of Arrivals/Beyond Light
As the Pyramid fleet back to consume the System, all Guardians convene at the City where the Traveler began to heal the damage to itself caused by the Red War. The Traveler appeared to regenerate itself by drawing in energy from all around it, brightening the skies as it healed. Eris Morn commented that the Traveler healing itself would not result in the end of the conflict between itself and the Darkness "Pyramids" that have been threatening the universe; it will merely cause the conflict to escalate. With that, the Traveler unleashed another pulse of Light to push the Darkness back.
The Traveler grants some of its mysterious powers to the Guardians that take the form of usable abilities in-game. Ghosts, the personal artificially-intelligent companions of Guardians, were made by the Traveler itself in its dying breath. Within the Tower, The Speaker acts as the representative of the Traveler.
- According to Fenchurch Everis, the inside of the Traveler "smells faintly of vanilla." Whether this is true or not is unknown.
- According to Xur, there is a dark mirror of the Traveler.
- Calus claims to have known of the Traveler before its arrival to the Solar System.