I already found thaniel. This is specifically about going back to the starting area in between the thaniel quest and the night song quest.
Did you restore Thaniel, or is he still catatonic?
It doesn't really matter at this point if you've found the other part because Halsin is going to want to stay with Thaniel after he's rescued him from the Shadow realm no matter what. If you want to return to previous areas and not lose Halsin, that needs to be done before you tell Halsin about Thaniel (in other words, before Halsin leaves to open the portal and bring him back). Halsin's quest was to find Thaniel and since Thaniel is in no condition to travel, Halsin will stay once he's found. Which sort of make sense, but I think it should have been implemented better with a clearer conversation about it as the party leaves, and also, make it clear Halsin will be waiting for the party's return rather than having the quest log say he left you and won't be helping.
