Agro is Wander's trustworthy horse and is the main form of transportation in-game aside from walking. Agro is very rarely able to participate in a colossus fight, and is only required for the battle with Dirge, Phalanx, and Basaran. Every time you defeat a colossus, Agro is back at the temple ready for the next colossus. Right before the battle with Malus, Agro falls off a falling bridge; throwing Wander off her back and saving him from sharing her fate.
During the credits, Agro greets Mono after she is revived with merely a limp on one of her back ankles. She leads Mono and the reborn Wander to the garden up a long ramp aside the structure, where they start their new life atop the temple.
- While Wander is resting, the camera will follow Agro as she explores the land freely until the music comes to an end. The route is not pre-recorded, so she will take a random course each time.
- Although stated that Agro is a male horse during the first few minutes of the game in the tutorial, Fumito Ueda himself has confirmed that Agro is in fact female.
- On the ICO™ and Shadow of the Colossus™ Collection, there is a silver trophy called "Agro Circus". You can acquire this when you perform all stunt riding using Agro.
- If you have a saved game file from Ico on your memory card, it will change the diamond-shaped mark on Agro's head to the "I" from the Ico logo. This works with the Ico and Shadow of the Colossus Collection on the PS3, as well.
- Agro is a prefix that usually refers to agriculture.
- Beating the time trials will give you the option to make Agro brown and beating them on hard mode will let you make her white. To do this, hold down the square (Brown) or circle (White) button when starting up your game.