The Heavy Horse Archer is mounted archer unit in Age of Empires that can be trained at the Archery Range once the Iron Age is reached. It is an upgrade of the Horse Archer and is highly effective given its cost. The upgrade increases the attack by 1 point, provides an additional 30 hit points, and slightly increases speed to make the unit the fastest in the game.
All cavalry archers are designed for guerilla warfare due to their supreme agility and can outrun most attacks dealt by enemy units. As a result, they excel at hit and run attacks and can repeat the process until the enemy is eliminated. Heavy Horse Archers also have the strongest human-based ranged attack in the game and are the fastest land units other than cheat units.
They have few counters, but among them is the PalmyranCamel Rider. The Camel Rider, who's a counter for all cavalry in general, also gets a 25% increase in speed as Palmyrans which makes them able to catch up and properly deal with Heavy Horse Archers.
"In a few armies of the late ancient period the Horse Archer was equipped with helmet and limited body armor. This made the archer less vulnerable to arrows himself. The Heavy Horse Archer could get closer to the enemy and do more damage with bow fire with less risk to himself. Heavy Horse Archers were not a common unit, however. They were difficult to train, except for those cultures who were horse archers by common practice. Body armor for archers was a luxury that most armies could not afford."