"Darkness"
Aud and Olaf's only child is born at midnight, with only the dim light of a single lantern to welcome her into the world. It's fitting, Aud later thinks. Daytime is devoted to housework, the livestock, Olaf; at night, Aud is solely for Ingrid. While Olaf snores, Aud lights the lantern and cradles her baby, staring with wonder while marveling that the gods would entrust her with something so precious.
Ingrid dies at noon, three months after her birth. For the rest of the day, Aud doesn't move; the sun sets, but she cannot bring herself to light the lantern.
"Light"
It's so easy, Aud finds, to retreat into darkness and hide from fear, pain, suspicion; to curl up in Olaf's arms at night and accept his tender words.
But then everything falls apart: a single beam of her lantern's light falls over Olaf and Rannveig, emerging disheveled and breathless from the forest. She's lost everything, Aud realizes; she can no longer hide in darkness now that the light has found her. She can only move forward, into the light, and wield the truth, have vengeance.
So Aud runs far and fast, the lantern her guide as she searches for eelsbane.