Dezzy's Closet
Savvy's Attic
Scarlet's Game Room
I know of 7 creatures that drop Rattlebones Master Duel. There could be more, I don't have the scoop on ALL the bosses out there yet. I been trying to get Alric to do my work for me - uh, I mean HELP me, but I haven't had much luck yet.
Name
Location
Jade Oni
Emperor's Throne Room, MooShu
Malistaire Drake
The Great Spyre, Dragonspyre
Othin Stormfather
Raven Fortress, Grizzleheim
Rattlebones
Rattlebones' Tower, Wizard City
Santa Muerte
Kondha Desert, Khrysalis
Starburst Spider
Mirror Lake, Zafaria
Tse-tse Snaketail
Mirror Lake, Zafaria