In Genshin Impact, after assisting Bona in purifying the Abyssal Corruption from the Chu'ulel Light Core, players must help her locate the Primal of Flame. Once found, Travelers must offer two Pyrophosphorites (obtained during the Palace of the Vision Serpent Quest) to the Altar of Primal of Flame.

This offering opens a path to Tonatiuh, a floating island above Ochkanatlan's Cradle of Fleeting Dreams. Reaching Tonatiuh completes the To the Sky-Road Quest and begins The Other Side of the Sky Quest, requiring the collection of four Burning Firestones to acquire the Jade of Return.

Obtaining the Four Burning Firestones:

Firestone #1

The first Firestone is obtained automatically during a cutscene with Bona and the Little One after reaching Tonatiuh. Follow the Little One, activate the lift mechanism, interact with the Saurian, and speak with Bona.

Firestone #2

The second Firestone is located on the northeastern isle. This requires manipulating the floating island mechanisms, crossing bridges, activating lifts, and defeating an enemy before collecting the Firestone and an Exquisite Chest. Return to the Altar of Primal of Flame with the Little One.

Firestone #3

To acquire the third Firestone, manipulate the floating island mechanisms to reach the northern isle's lower level. Follow the Little One, observe the Secret Source Sentinel's actions, utilize a Qucusaurus to reach the Pyroculus, activate mechanisms, and retrieve the Firestone. Return to the Altar via the lift.

Firestone #4

The final Firestone is on the northwestern isle's upper level. Use Bona to adjust the bridge, glide to the upper level, and follow the Little One. Defeat enemies, collect a Precious Chest, and return to the Altar with the Little One.

Offering all four Firestones to the Altar completes The Flowing Primal Flame Quest, transforming the Jade of Return into a Golden Entreaty. The Dragon of the City of Flowing Ash then appears, leading players to the Nursery of Nightmares island to finish The Other Side of the Sky Quest and receive 50 Primogems.