Vile's A Multi-Reference Villain For Megaman X!
During the first game, the story of the first Megaman X game somewhat parallels the first Megaman game. Vile happens to be some kind of prototype Maverick Hunter that went defective. During Sigma's rebellion when most of Dr. Cain's robots rebelled no thanks to Sigma. Like Protoman, Vile joins the rebellion where he becomes an evil version of Protoman. I felt like he's meant to be a hybrid of both Protoman, the 3rd Darkman Robot and the 4th Darkman Robot. The third Darkman Robot somewhat fights like Vile and the fourth one was disguised as Protoman. Speaking of the Darkman Robot, the fight between him and Megaman X somewhat resembles the final Darkman Robot battle. You have the Darkman Robot depleting Megaman's energy then you have Vile doing the same to Megaman X. Protoman restores health to Megaman and Zero restores health to Megaman X but with a more grim outcome.
Another character fans compare him to is Bass. While Bass feels to be more of an honorable opponent with the Vegeta-like complex, Vile doesn't do any fair fights and prefers to fight dirty. While Bass rebels against Dr. Wily, Vile remains as Sigma's henchman. Vile would later appear again in Megaman X3 where I felt his events were a reversal of Protoman's. Megaman 3 redeemed Protoman but Megaman X3 doesn't redeem Vile at all. He's supposedly defeated yet again but manages to mysteriously return.
During Megaman X8, he does somewhat appear randomly in the place of certain score-based mini-games as that heckler. Protoman did the same thing in Megaman 3 in some stages of the game. But unlike Protoman, he's still evil nonetheless.