Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Wailing Terror Leggings Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Wailing Terror Leggings suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Wailing Terror Leggings is part of the transmog set Eternal Curator's Vestment (Priest, Mage and Warlock only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 161387 (161382 to 161392) were usually added in the same batch as Wailing Terror Leggings: the same quest line, zone, vendor or reward set.