This is an expansion and requires the base game to play: Yes

Expand your game to include 6 players, with 6 new asymmetrical starting decks with thieving identities!

The thieves’ guild is recruiting! Clank! Adventuring Party expands your merry band to include up to six players in your dungeon run! Want a new thieving identity? Shuffle up as one of six unique characters, each with their own starting deck and special abilities!

Lead trusty companions as the Dwarf Agnet
Build wonderous collections as the Elf D’allan
Smash hordes of enemies as the Orc Garignar
Sling arcane spells as the mage Lenara
Amass primate power as the MonkeyBot Prime
Or stir up a paw full of trouble as the devious cat Whiskers
But beware: the ravenous hydra Hexavultus won’t give up his treasures easily...