The raven embodies the duality of life - light and dark, life and death, creation and destruction; partly due to their black feathers and their presence in folklore as creatures of the night. They are the messengers between the physical world and the spiritual realms.
They are connected to the underworld acting as guides between the living and the dead.
Goddess Association:
Morrigan: In Celtic mythology, the goddess Morrigan is often depicted as a raven or in the company of ravens. She is a goddess of war, fate, and death.