The rank classifications for knights and mages are as follows.
1st 2nd circle (apprentice mage) = mana user (apprentice knight)
3rd 4th circle (regular mage) = aura user (regular knight)
5th 6th circle (high-ranking mage) = aura expert (high-ranking knight)
7th circle, wizard (great mage, title) = aura master (knight commander, title)
8th circle, grand wizard (great mage, title) = grand master (knight commander, title)
9th circle, lord wizard (great mage, title) = lord master (knight commander, title)
As a high-ranking knight, he corresponded to the 5th 6th circle if translated into mage terms, and 'Vanguard' referred to a special combat force equipped with the tactical gear known as 'Force Armor' and 'Force Sword.'