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 the collection of four Burning Firestones to acquire the Jade of Return.
Obtaining the Four Burning Firestones:
Burning Firestone #1
The first Firestone is obtained during a cutscene after reaching Tonatiuh. The Little One will collect it; follow it across a raised bridge (using a nearby mechanism) and interact with the Saurian and Bona.
Burning Firestone #2
The second Firestone is on the northeastern isle. This involves manipulating floating island mechanisms to extend bridges, raising a lift, and following the Little One. Along the way, collect a Common Chest and an Exquisite Chest (after defeating an enemy and activating a mechanism). Finally, return to the Altar via the Little One.
Burning Firestone #3
To acquire the third Firestone: manipulate floating island mechanisms to access the northern isle's lower level, follow the Little One, and observe a Secret Source Sentinel carrying the Firestone to the southwestern isle. This requires using a Qucusaurus to reach the Pyroculus, activating a tower mechanism, and utilizing an elevator. After interacting with the Saurian and activating a lift, return to the Altar.
Burning Firestone #4
The final Firestone is on the northwestern isle's upper level. This involves crossing a bridge (using Bona to adjust its angle), gliding, lowering a lift, following the Little One, defeating enemies, collecting a Precious Chest, and returning to the Altar.
After offering all four Firestones to the Altar, the Jade of Return transforms into a Golden Entreaty, triggering a cutscene with the Dragon of the City of Flowing Ash. This leads to the Nursery of Nightmares island, completing The Other Side of the Sky Quest and rewarding players with 50 Primogems.
