Eagle, or called Commanded Eagle, is an unique ability possessed by Blackmist as Armed with Wings. That means, Blackmist is not seen controlling eagles apart from an agent as Armed with Wings.
Commanded Eagle effectively controls a nearby eagle, Armed with Wings can command the eagle to reach remote locations, to fetch items, tow them and trepass tricky places such as pitfalls. This is often against the freewill of a wild avian. Although shared vision is not mentioned, the eagle can sense differnt switches and perform complex tasks by the will of Armed with Wing, even if he cannot see or hear anything around the eagle.
The ability has a limit according to the properties of Armed with Wings. Lone Warrior has weaker control on the eagle, granting limited control time unless a powerup is obtained. Leo although has timeless control on commanding the Eagle, it cannot exceed natural flight abilities, nor does it allow exaggreated actions such as towing Leo altogether, or participating in any combat. Acting as a climb assistance however, the eagle can do this.
The ability can be existant even before the person has not realized he is Armed with Wings, and the commanding ability will not be hindered. Losing the status however, will cause the ability to be lost as well.
The eagle is apparantly made of Blackmist, but whether it will be destroyed when Armed with Wings is defeated or lost the status is unknown. The eagle dies when Lone Warrior dies in AWW1, while the eagle does not die when Leo dies in AWW3. Strangely, everyone except Armed with Wings are completely unaware of the Eagle (seeing it as a regular bird) and the ability, despite the lore says Armed with Wings is related to a eagle.