i donated every elf with level 1 until i had 20 and there i am the quest doesnt go furtherSince this Quest spams your Questlog i decided to stay out of the forest as long as i can, so that this questspam will happen later. But if i would need to guess. Create many Elfes (20+) level them to 10+ (no idea iof necessary) and then spend them.
I can only say for sure that this quest was long active, but triggered short after i spend a new batch of leveled elves