who is Hermes and what is his mission?

Athena pleads to the gods and Zeus at Mount Olympus on behalf of the imprisoned Odysseus and Telemachus, who is in danger of being ambushed. Zeus tells her to protect Telemachus, and sends Hermes to order Calypso to release her prisoner. Hermes races to Calypso's beautiful island. He gives the goddess Zeus' command. She reluctantly agrees, but not before pointing out that male gods are allowed to take mortal lovers while female ones are not.

Hermes is the messenger of the gods.