The raven has many meanings. First of all, it symbolizes the Norse god Odin and the Greek god Apollo, who had ravens. Odins ravens were called Hugin (thought) and Munin (memory). Also, Odin was omniscient. Therefore people believed that the raven (or the crow) could foretell the future, but also the hidden truth. This we also saw in Game of Thrones with the three-eyed-raven who was omniscient. Who could see the past, present and future.
Also, when someone is dying, a raven or crow appears, a sign of the nearing death. The bird knows that the person is dying.
Ravens and crows also appear on the battle field, after the combat, to eat the corpses.
In alchemy the raven symbolizes melancholy and in Christianity the raven is the sinner, or the Devil. That is because the raven never returned to Noach’s ark (the dove did).
But birds in general are the connection between heaven and earth. They are spiritual creatures. That makes the meaning of the raven and crow twofold: they are death/darkness/the Devil, but also the connection to the spiritual realm, to God. You might say that they are the messengers of the dark, unknown side of God.
This ambiguity is not strange. We also find it in language: black and blank (white) have opposite meanings, but the same root. The same counts for bad and better (badder). And divine and devil.
This is how you might perceive the raven and crow: they bare opposite meanings of the same root.
