The nighttime cave meeting after the Laslea errands
Neberu appears in the epilogue quest Things Will Be Different Now, after the confrontation with Brencis. You can speak with him in Laslea; if you did not meet him in the village, the closing cave scene introduces him.
On the epilogue route through Laslea, finish the village errands and take the peat to Anca’s hut. Her potion and the following conversation move the sequence into night. After the cutscene, climb the rock walls with Shadowstep and continue to the large cave to reach the meeting.
The villagers and errands you encounter depend on who survived the story. Follow the objectives in your epilogue until the nighttime climb becomes available. Keep a save before the final assault if you want to return to unfinished quests or compare a different ending.