Which Assassin's Creed game first introduced the playable Eagle Vision ability?

Assassin's Creed first introduced the playable Eagle Vision ability.

Eagle Vision is a perception ability associated with the protagonist Altaïr Ibn-La'Ahad in the original game. It highlights people and objects by alignment or relevance, helping the player identify targets, allies, guards, and investigation points within the historical world.

The ability is presented as a gift connected to the Assassin lineage and the series' broader eagle symbolism. Later protagonists use related versions of the skill, although its visual presentation and gameplay functions change across different entries.

Eagle Vision should not be confused with the controllable bird companions introduced in later games. Assassin's Creed Origins and Odyssey use eagle-based scouting systems, but they do not mark the first appearance of Eagle Vision itself. The original title established the ability as part of the series' core vocabulary.