From Destinypedia, the Destiny wiki
Axis Minotaurs are a more lethal variant of the standard Minotaur chassis. They are seen in various Patrols, Public Events, and Missions regarding the Vex. Like most Major class enemies in Destiny 1, Axis Minotaurs bears the same appearance as the normal Minotaurs, except their health bar, which is colored yellow rather than the normal red. Axis Minotaurs are also resilient against certain weapons.
List of appearances