Tyr said that you should go to Hreidmar, the guardian of the area where the Observatory is located, and find out if there's a problem with the Nepra trees. Hreidmar said he couldn't place his faith in you until you earned the trust of Ahin. Ahin gave you a Token for gaining Hreidmar's trust. He sent you to scout the local Mau, who were killing the Nepra trees. You killed the Mau priestess responsible for the deaths of the Nepra trees.