From publisher blurb:
When Swords for Hire Development pitched the Villain Codexes to Outland Entertainment, we only envisioned three volumes, bringing us two evil-doers from each of CR 3–20. But villains have a way of foiling the best-laid plans.
Villain Codex IV: Monsters for Meddlesome Heroes draws from iconic monsters in the Pathfinder Roleplaying Game (faerie dragons, treants, unicorns) as well as new favorites (gremlins and leshies) to expand upon the monstrous villains introduced in Villain Codex III: Enemies for Epic Heroes.
Villain Codex IV: Monsters for Meddlesome Heroes includes monstrous villains from CR 3-14.