This page explains how to complete the level 80 post-Shadowbringers quest "Heroic Dreams".
Requirements
This quest is available if you have completed the quest In the Name of the Light.
Starting the Quest
Talk to Eirwel in the Crystarium to begin the quest.
Speak with Alisaie at the Exarch Gate
Go southeast through one of the archways, then go south to the stairs. Go west up the stairs and use the Aetheryte to go to Tessellation (Lakeland). Then go west to the quest icon and talk to Alisaie to proceed.
Use Heat Lures to Draw Out Vampire Bats
You can either teleport to Fort Jobb or you can go north to the northernmost orange circle on the map. Go to the east side of this orange circle, then dismount and target the Destination, and then you can either examine or target it and use the Heat Lure on it from the Key Items section of your inventory, or you can target it and use the icon to the right of the quest name in your list of active quests. Kill the three Vampire Bats that attack.
Then go southwest to the northwest orange circle on the map. Go to the northeast part of this orange circle and repeat the steps from the previous paragraph to use a Heat Lure on the Destination. Kill the two Vampire Bats that attack.
Then go southwest to the southwestern orange circle on the map. Go to the southwest part of this orange circle and repeat the steps from the previous paragraph to use a Heat Lure on the Destination. Kill the three Vampire Bats that attack.
Deliver Bat Fangs to Ryne
Go northeast to where the orange arrow is pointing in the minimap. Talk to Ryne to proceed. There will be a cutscene.
Go to the Lookout in the Crystarium
Go east into the Crystarium. Go northeast until you can go northwest to where the orange arrow is pointing in the minimap. Go up the stairs of the tower. At the top, check on the sparkling Destination. There will be a cutscene.
Speak with the Crystal Exarch
Talk to the Crystal Exarch to complete the quest.
Next Main Scenario Quest
After you complete the quest, talk to Ryne to accept the next quest: Fraying Threads.