Tirisfal Regalia is the tier 5 mage set.
The Tirisfal Regalia items are sold by Kelara (Aldor) or Veynna Dawnstar (Scryer) in Shattrath City. They are "purchased" with Tokens of the Vanquished Hero.
Tirisfal Armor on a male human.
It should be noted that the Tirisfal Armor bears a striking similarity to Medivh's robes. Given the name, and that Guardians resided in Tirisfal, it could be assumed that this is the "standard" armor of either Guardians or perhaps the Council of Tirisfal.
This set is worn on the official mage avatar.