This WoW set features the full Absolution transmog, which is the priest tier 6 raid set. Absolution is obtained by looting armor tokens from various Burning Crusade bosses. These tokens can be traded for set pieces via Shattrath City tier vendors. Note that, originally the tier 6 priest set was only a six piece set, but later changed to include non-matching feet, wrist, and belt, as they still match other Sunwell Plateau raid gear. Matching non-set belt and feet are provided next to the sets below.
How to Get Priest Tier 6? By slaying Hyjal Summit, Black Temple and Sunwell Plateau bosses.
Are There Multiple Tier 6 Transmogs For My Class? No, some classes do have multiple tier 6 sets (depending on their class trees), but every tier set variation features the same exact transmog look. For example, the paladin has a different set for retribution, holy, and protection, but all three sets share the same exact model and color variation. (Hunter, Mage, Rogue, and Warlock feature only one tier 6 set)
How Many Set Pieces?  Helmet, Shoulders, Chest, Bracer, Hands, Belt, Pants, and Feet.
Priest Tier 6 Transmog: [Drop Locations]
Note: Priest have two different sets with the same exact look. Tier 6 priest armor tokens can be used to purchase any of the set pieces.
Head: Helm of the Forgotten Conqueror [Archimonde] in Hyjal Summit.
Chest: Chestguard of the Forgotten Conqueror [Illidan Stormrage] in Black Temple.
Wrist: Bracers of the Forgotten Conqueror [Sacrolash – Alythess] in Sunwell Plateau.
Hands: Gloves of the Forgotten Conqueror [Azgalor] in Hyjal Summit.
Waist: Belt of the Forgotten Conqueror [Brutallus – Alythess – Sacrolash] in Sunwell Plateau.
Legs: Leggings of the Forgotten Conqueror [Gathios – Malande – Veras] in Black Temple.
Feet: Boots of the Forgotten Conqueror [Felmyst – Sacrolash – Alythess] in Sunwell Plateau.
Vendor 1: Theremis [50,28] in Isle of Quel’Danas sells the [Waist, Wrist, Feet] Vendor 2: Tydormu in Hyjal Summit raid instance sells [Head, Shoulders, Chest, Hands, Legs]
Set Name: Absolution Regalia (hover for set bonuses)
Shoulder: Shoulderpads of Absolution
Chest: Shroud of Absolution
Wrist: Bracers of Absolution
Hands: Handguards of Absolution
Waist: Cord of Absolution [Transmog Alternative: Belt of Divine Guidance] Legs: Leggings of Absolution
Feet: Treads of Absolution [Transmog Alternative: Archbishop’s Slippers]
Set Name: Vestments of Absolution (hover for set bonuses)
Shoulder: Mantle of Absolution
Chest: Vestments of Absolution
Wrist: Cuffs of Absolution
Hands: Gloves of Absolution
Waist: Belt of Absolution [Transmog Alternative: Belt of Divine Guidance] Legs: Breeches of Absolution
Feet: Boots of Absolution [Transmog Alternative: Archbishop’s Slippers]