Super Bass and Absolute Zero?
Bass being introduced as a villain in Megaman 7 then an anti-hero in Megaman Power Battle and Megaman Power Fighters may have left a legacy on the X series as well. In Megaman X7, Axl is too obviously based on Bass from Megaman 7 and note both names of Axl and Bass are sound based. So let's think of another tribute to him.
Absolute Zero from Megaman X Command Mission. I just thought though that this form SHOULD have been given to Axl instead of Zero since Axl is closer to being a Bass tribute than Zero (who is also created by Dr. Wily) ever is.