Ath'kethin
Elder Thing
Definitely not every session, but definitely every adventure.
Though I'm using the concept of "dungeon" fairly loosely here, as in "building/structure with numbered rooms full of traps, monsters, and treasure." Which may or may not be the intended definition for the question.
Though I'm using the concept of "dungeon" fairly loosely here, as in "building/structure with numbered rooms full of traps, monsters, and treasure." Which may or may not be the intended definition for the question.