In Crushbone (regular low level zone): These guards are found inside the castle, near the throne room. They see invis.
In Crushbone (Level 90 revamp): These guards are found inside the castle, near the throne room.
In Crushbone (Level 90 Raid): Part of the "Demise of the Emperor" mini-raid event (see this quest entry for event and loot information).
In Blackfeather Roost: (no data)