Radiance

The Radiance is a higher being of light similar to Essence, and as such, opposed to the Void, her ancient enemy. The Moth Tribe is born from her light and in return revered her.

After the Pale King arrived in Hallownest and expanded the minds of his new subjects, the Moth Tribe turned their backs on the Radiance and worshipped him instead. In doing so, the Radiance was almost entirely forgotten, yet traces of her memory remained, such as a statue on Hallownest's Crown. Her memory started spreading throughout the Kingdom, by then in its golden age. Soon, all of Hallownest began to dream of her appearing to them as a blazing light. These dreams could break the minds of bugs and eventually enslave their wills to her. However, the King and his subjects resisted her memory, which then started to manifest as the Infection. With the Infection, the Radiance offered unity to bugs at the cost of a mind incapable of thought.

The Pale King attempted to stop the Infection by sealing the Radiance within a Vessel. These creatures, infused with the Void to be without a mind and without a will, were to be able to withstand the Radiance's influence. The Hollow Knight was chosen, raised, and grown for that purpose. The Radiance was sealed within them, and the Vessel was chained within the Temple of the Black Egg. However, the Vessel had attained impurities of mind. Because of this, the Radiance was still able to invade the dreams of bugs. She ultimately wiped out the inhabitants of the Kingdom, whose King had vanished, but left the rest of the land untouched.

Time passed, Hallownest turned into a myth while the Radiance remained sealed. Her influence finally started to break out of the Hollow Knight. She reignited the Infection, threatening again the land of Hallownest and prompting the Knight to return.