This page explains how to complete the level 88 Endwalker quest "Once Forged".
This quest is available if you have completed the quest Hither and Yarns.
Starting the Quest
Talk to G'raha Tia in Labyrinthos to begin the quest.
Speak with G'raha Tia
Go south through the archway, then go southeast to where the orange arrow is pointing in the minimap. Before you go to the quest icon, use the Aether Compass (Main Menu > Duty > Collection) to find an Aether Current to the southeast. Check on the Aether Current to attune to it. Then go to the quest icon and talk to G'raha Tia to proceed.
Survey the Designated Location
Go northeast to the quest icon and check on the Destination. Defeat the Swirling Apa that attacks, then defeat the two Swirling Sprites that attack, then defeat the two Swirling Apa that attack.
Survey the Designated Location Again
Check on the sparkling Destination to proceed. There will be a cutscene.
Speak with Kokkol Dankkol
Go east through the archway, and continue going east to where the orange arrow is pointing in the minimap. Talk to Kokkol Dankkol to complete the quest.
Next Main Scenario Quest
After you complete the quest, talk to Kokkol Dankkol to accept the next quest: Bonds of Adamant(ite).