An entity is a PC, Adversary, Challenge, or Opponent within a scenario. In other words, an entity is a player's character or a character controlled by the DM, whether ally, enemy, or neutral party.

While many games use “character” for the generic term, Triptycho features non-character hazards such as Traps, storms and weather, fearsome ambiance, and all manner of similar things that often take turns and behave much the same as traditional characters. For this reason, the term “entity” is employed to refer to all of them from a game mechanics perspective.