Aeon is a one of the main antagonists of Final Fantasy Sonic X.
He is an antropomorphic hedgeogh with a white and green color scheme. He works for Cain's organization as a commander, along with his partner Bass. He is Sonic's main rival in the series. He can punch and kick. He can also turn one of his arms into a Megaman style cannon capable of shooting green energy beams.
Aeon and Bass knock out Link, before appearing in front of Sonic and his friends. Aeon orders Sonic to give him the Stone, but Sonic refuses. This makes Aeon and Bass teleport away, leaving the True Guardian to fight Sonic. Their plan is to let the True Guardian defeat Sonic for them, so that they can steal the Stone and the Mysterious Sword from the blue hedgeogh afterwards. Megaman X and Zero leave Sonic, searching for Aeon and Bass. Aeon teleports in front of Megaman X and Zero in a forest, starting a fight with the two. After the battle Aeon remembers Megaman X of his past, where the blue reploid used to work for Cain's organization. After this Aeon teleports away.
Aeon and Bass are standing in a grassland called Elysium. Tails and Knuckles are running across it, searching for Sonic. Tails keeps running until he collides with Aeon. Aeon reacts by kicking the fox away. Aeon orders Knuckles to give him the Master Emerald, but Knuckles refuses. Knuckles and Tails then proceed to fight Aeon and Bass. Knuckles and Tails are losing, until the fox uses an Overdrive, a powerful combo attack wich defeats Aeon and destroys Bass's flying armor, leaving this last one injured.
Despite losing the battle against Knuckles and Tails in episode 4, Aeon and Bass gain the upper hand offscreen, defeating Tails and Knuckles. Sonic, after defeating the True Guardian, arrives and sees Tails and Knuckles lying on the ground, defeated. This sight makes Sonic angry, making him kick away Bass and making him start a fight against Aeon.
The battle between Sonic and Aeon continues, with Sonic coming out victorious. Sonic is about to land a kick on Aeon's unconscious body, but Bass shoots a laser at him. Bass, having defeated Sonic, lets him keep the Stone and the Mysterious Sword, so that he can manipulate him later on. Bass then goes away with Aeon's body, putting him in a healing pod at Cain's base, so that he can recover.