Megaman X4 - Maverick Zero vs Sigma

This is the song for the Past of Zero, before he became a Maverick Hunter, when Sigma was the Commander of the Maverick Hunters and after punching Zero's W Crystal he was infected with the....¿Zero Virus? I think that's the Virus that made Sigma a Maverick. Megaman X and all other copyrighted and Registered Material is property of their respectful owners(Capcom,etc.)