Lagertha realizes that Freyja’s fertility is meant for another, and that it is the goddess warrior aspect that speaks to her fellow Valkyrie.
Although the sources consulted are not clear on this, the chief of the Valkyries seems to have been the goddess Freyja.
She is the Norse goddess of love, fertility, and beauty, sometimes
identified as the goddess of battle and death. Blond, blue-eyed, and
beautiful, Freyja travels on a golden-bristled boar or in a chariot
drawn by cats. She resides in the celestial realm of Folkvang. Like
Odinn, she received half of those slain in battle, but since ladies go
first she was allowed first choice!
Freyja possessed a magical cloak of falcon feathers
that allowed her to take the shape of a falcon if she wished, making
the swan maidens similar to the goddess by having “feather coats” or
cloaks that enable their shape-shifting abilities and the power of flight.