Io

"Io was the last place visited by The Traveler, and the site of great interest to both humanity and the timeless Vex machines. The Red Legion, too, now seek to unravel the secrets and power of this place, gouging at the surface, seeking to uncover new sources of power to aid in their quest to dominate our worlds. It is up to you to protect this place, and preserve its great legacy."

- Website description

Io (also called Jupiter I) is one of the four major moons of Jupiter.

Overview
In the final days of the Golden Age the Traveler was in the midst of terraforming Io when it detected the Darkness approaching; abandoning the moon it fled to Earth. As a result of this the Ioian climate and geography do not support traditional agriculture, meaning some remnant of Io's original atmospheric composition prevented the growth of plants. Echo Mesa, a mountain on Io, has become a popular pilgrimage site for Guardians.

One of the legends of the Nine state they are some of the original Awoken transcended to mental form and live inside the Jupiter-Io.

History
During the The Red War, Io became a warzone for Guardian, Red Legion, Fallen, and Vex forces. Io was the final place that the Traveler influenced with Light in the Solar System. Io is also a sacred ground for Warlocks.

List of appearances

 * Destiny
 * Age of Triumph
 * Destiny 2