Kassandra's eagle in Assassin's Creed Odyssey is named Ikaros.
Ikaros is a golden eagle that helps Kassandra scout the landscape, mark enemies, locate resources, and identify important objects from above. This bird-based reconnaissance system continues a feature introduced in Assassin's Creed Origins, where Bayek uses his eagle Senu.
Odyssey is set in ancient Greece during the Peloponnesian War, beginning in 431 BCE. Kassandra is one of the game's two selectable protagonists; the player can instead choose Alexios. Ikaros is associated with Kassandra's version of the story, while Alexios uses the same character role when selected.
Ikaros is easy to confuse with Synin, the raven used by Eivor in Assassin's Creed Valhalla, or Senu, Bayek's eagle in Origins. Darius is a human character from the series, not a bird companion.