Blizzard numbers items as they are created, so the named items next to ID 251531 (251517 to 251540) were usually added in the same batch as Void-Scarred Seer's Shawl: the same quest line, zone, vendor or reward set.
Shield of Unending WoeID 251517 · Armor - Shield"Enemies may instinctively target the shield over the wielder."
Key of Fused DarknessID 251519 · Key"A mysterious key whose properties defy all logic."