The Eternal Palace is a separate section of the White Palace and holds the truths about the Pale King and his secrets. The quest can be activated at any time, but the journey to the White Palace can only begin after the defeat of the Radiance or Pure Vessel (in a Pantheon, NOT the Hall of Gods).
The Eternal Palace quest features a journey into back into the White Palace, which has been reformed by the Pale Titan into the Eternal Palace, where you are battling various bosses and enemies and seeking the truth behind the Pale King’s life. The DLC fixed bugs and glitches + added and entirely new quest line revolving around the White Palace and the Pale King, as well as new charms, bosses, items, and more. Voidheart Edition Eternal Palace is the fifth and final content pack for Hollow Knight, released on Februas a Hollow Knight refresh update and extra content while players continued their wait for Silksong.