Read from the World of Warcraft client build files (JournalEncounterItem, JournalEncounterCreature, Achievement) and the Blizzard Game Data quest API.
How Hardened Castle Crushers Compares
Who It Suits
Plate is the armor type Death Knight, Paladin and Warrior wear. With Strength or Intellect, Hardened Castle Crushers suits Arms, Fury and Protection Warrior; Holy, Protection and Retribution Paladin; Blood, Frost and Unholy Death Knight.
Transmog Sets
Hardened Castle Crushers is part of the transmog set Grand Sentinel's Greatplate (Warrior, Paladin and Death Knight only). The other 16 pieces:
Blizzard numbers items as they are created, so the named items next to ID 184171 (184166 to 184176) were usually added in the same batch as Hardened Castle Crushers: the same quest line, zone, vendor or reward set.
Corridor CreeperID 184166 · Miscellaneous · item level 10"Teaches you how to summon this mount."
Mawsworn SoulhunterID 184167 · Miscellaneous · item level 10"Teaches you how to summon this mount."
Bound ShadehoundID 184168 · Miscellaneous · item level 10"Teaches you how to summon this mount."