Pathfinder RPG Bestiary 4 Essentials:

• No. of players: 2
• Playing time: ∞

Pathfinder RPG Bestiary 4 - Rules of Play says:

Confront the creatures that go bump in the night! Bestiary 4 presents hundreds of new monsters for use in the Pathfinder Roleplaying Game. Within this tome of terrors you'll find pitiless psychopomps and blood-drinking nosferatu, insectile formians and faceless nightgaunts, and even unique mythological horrors like Spring- Heeled Jack and Grendel himself. Yet not every creature need be an enemy, as mighty empyreal lords, primeval outer dragons, and valorous swan maidens enlist you in their epic battles!