The Legion is in retreat following a failed battle against the armies of the undead. You are a member of the Legion, your bonds to one another forged in the dark by bone and blood.
Now you have have reached Talgon Forest, which grows more mystical by the day. The Panyar brought a cutting from their Heart Tree a few hundred years ago and now the paths and trees are becoming prone to shifting. A sacred site to the Horned One is hidden here too, and she has great power to offer you. Talgon Forest is one of the most pristine places left in Aldermark, but that does not make it safe. The forest does not care for intruders, and the Legion are only marginally better than their undead counterparts in the eyes of those things that call the forest home.
When the Chosen of the Moon Goddess Nyx faced the undead Cinder King, he Broke her, as he has Broken so many of the Chosen. The moon shattered and fell from the sky. A huge fragment of it lies in the Talgon Forest, and such a powerful and holy relic would be invaluable in the war.
Put a team together, choose your unit, and go and fetch it.