Rasho has a few words of advice before you depart to meet with the Kojin.
This quest is available if you have completed the quest Alisaie's Stones.
Starting the Quest
Talk to Rasho in the Ruby Sea to begin the quest.
Search for Lyse
Go down the stairs to sea level, then go southeast to the orange circle on the map. Go to the southeast edge of the orange circle (to the end of the pier) and talk to Lyse. There will be a cutscene.
Go southeast to where the orange arrow is pointing in the minimap. Go to the south side of the orange circle and talk to Alisaie to proceed.
Search for the Blue Kojin Village
Go south through the narrow passage and look for the cave entrance in the wall to your right. When you find Lyse, go to the left and make your way down the slope. Eventually you will see a cave entrance and Alisaie up ahead. Approach Alisaie and there will be a cutscene.
Speak with Alisaie
Talk to Alisaie to complete the quest.
Next Main Scenario Quest
After you complete the quest, talk to Soroban to accept the next quest: Of Kojin and Kami.