Fundament

Fundament is a massive gas giant that was the birthplace of the Hive's ancestors. It was originally home to a peaceful serpentine species that later embraced the Witness's Sword Logic, leading to catastrophic conflict. Survivors became the Worm Gods, six entities including Xol and Yul, trapped in the planet's core. The Krill who lived on its floating continents later pact with the Worms, gaining immortality and the larvae that made them the first true Hive.

Within Destiny 2 it is only mentioned in passing, in the Warmind expansion and Season of the Worthy.