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 present 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.
Locating the Four Burning Firestones:
Burning Firestone #1:
The first Firestone is obtained automatically during a cutscene with Bona and the Little One after reaching Tonatiuh. Follow the Little One across a raised bridge.
Burning Firestone #2:
The second Firestone is on the northeastern island. Activate the floating island mechanisms to extend bridges, raise lifts, and follow the Little One. Combat and chest rewards are along the way.
Burning Firestone #3:
To obtain the third Firestone, manipulate the floating island mechanisms to reach the northern island's lower level. Follow the Little One, observing the Secret Source Sentinel's actions. This involves utilizing a Qucusaurus to reach a tower, activating mechanisms, and using an elevator.
Burning Firestone #4:
The final Firestone is on the northwestern island's upper level. Use Bona to adjust a bridge, glide to the island, and follow the Little One. Defeat enemies and collect a chest before returning to the Altar.
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 to the Nursery of Nightmares and the completion of The Other Side of the Sky Quest, rewarding players with 50 Primogems.