Combat Aura was an aura that was extracted and processed from human life source using a special breathing technique. It was different from magic energy or special ability of a mage, which was converted from mental strength. Combat Aura was a pure form of energy, which was different from the complex and ever-changing magic energy. It was impossible to release Combat Aura without reaching Silver tier or higher. It had the capability to enhance the overall performance of the user, including improvement in five senses, muscle and tendon strengthening.
However, the form of energy within the steel-essence crystal was different.