Read from the World of Warcraft client build files.
How Diabolic Mantle Compares
Who It Suits
Cloth is the armor type Mage, Priest and Warlock wear. With Intellect, Diabolic Mantle suits Discipline, Holy and Shadow Priest; Arcane, Fire and Frost Mage; Affliction, Demonology and Destruction Warlock.
Transmog Sets
Diabolic Mantle is part of the transmog set Diabolic Raiment (Warlock only), which the Appearances collection lists in 4 versions. The other 16 pieces:
Built from the World of Warcraft client build files and recorded Auction House snapshots.
Where Diabolic Mantle Fits
Other Items Named Diabolic Mantle
3 other items in the current build are also called Diabolic Mantle. Same-name entries are usually a different rank, faction, quest stage or reward track of the same object.
Blizzard numbers items as they are created, so the named items next to ID 247139 (247134 to 247144) were usually added in the same batch as Diabolic Mantle: the same quest line, zone, vendor or reward set.