Raven

Ravens are large black birds similar in appearance to crows. They are present in both Greek and Norse mythology.

Magnus Chase and the Gods of Asgard
Ravens are seen through Hotel Valhalla. They usually order Einherjar to the feast hall or drag the unwilling to battle practice.

The Tyrant's Tomb
A conspiracy of ravens attack Apollo, Meg McCaffrey, and Reyna Ramírez-Arellano as the three climb Sutro Tower. When Apollo explains he punished crows by turning them from white to black as punishment for informing him that his pregnant girlfriend Koronis was cheating on him and that he had Artemis kill her and save their child, Asclepius, the girls are outraged.