In Genshin Impact, after assisting Bona in purifying the Abyssal Corruption from the Chu'ulel Light Core, players must help her find the Primal of Flame. Once located, 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 Travelers to gather four Burning Firestones to acquire the Jade of Return.
Obtaining the Four Burning Firestones:
Burning Firestone #1
The first Firestone is obtained automatically after the cutscene with Bona. Follow the Little One across the bridge (activating the lift mechanism as needed) and interact with the Saurian and Bona.
Burning Firestone #2
The second Firestone is on the northeastern island. This involves manipulating the floating island mechanisms, crossing bridges, activating lifts, and defeating enemies. Remember to collect chests along the way! Finally, return to the Altar with the Little One.
Burning Firestone #3
To get the third Firestone, manipulate the island mechanisms to reach the northern island's lower level. Follow the Little One, observing the Sentinel's actions. You'll need to utilize a Qucusaurus to reach the Firestone, then activate mechanisms, and return to the Altar.
Burning Firestone #4
The final Firestone is on the northwestern island's upper level. Use Bona's assistance to reach the island, activate the lift, and follow the Little One back to the Altar. Defeat any enemies encountered. Collect the Precious chest before reaching the altar.
Offering all four Firestones to the Altar completes The Flowing Primal Flame Quest, transforming the Jade of Return into a Golden Entreaty. A cutscene will follow, introducing the Dragon of the City of Flowing Ash. Continue to the Nursery of Nightmares island to finish The Other Side of the Sky Quest and receive 50 Primogems.