Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Doomsayer's Ritualistic Vestment Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Doomsayer's Ritualistic Vestment suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Doomsayer's Ritualistic Vestment is part of the transmog set Diabolic Raiment (Warlock only). The other 16 pieces:
Items Numbered Next to Doomsayer's Ritualistic Vestment
Blizzard numbers items as they are created, so the named items next to ID 147733 (147727 to 147738) were usually added in the same batch as Doomsayer's Ritualistic Vestment: the same quest line, zone, vendor or reward set.