Read from the World of Warcraft client build files.
How Demonbone Waistguard Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Demonbone Waistguard suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Demonbone Waistguard is part of the transmog set Necrotic Boneplate Armor (Death Knight only). The other 16 pieces:
Built from the World of Warcraft client build files and recorded Auction House snapshots.
Where Demonbone Waistguard Fits
Other Items Named Demonbone Waistguard
2 other items in the current build are also called Demonbone Waistguard. 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 78645 (78638 to 78652) were usually added in the same batch as Demonbone Waistguard: the same quest line, zone, vendor or reward set.