Monster Monday - Monster Theme

The boss of a dungeon is an important thing. If you don't know what the boss of the dungeon is, you often end up with a "monster hotel." Today, for a change of pace, I thought I would go through a thought experiment. I am going to take a theme, and build an adventure outline based on that. Because it is Monster Monday, I will stay away from puzzles and traps.

An orcish shaman, recently uncovered an ancient tablet. This tablet pulses in the space between the Elemental Plane of Earth and the Prime Material Plane, bringing creatures to the shaman. He hopes to unlock its secrets, allowing him greater control over the creatures that keep showing up. The monsters travelling through the nearby farmlands should be enough of a plot hook to get adventurers moving.

The adventure is initially easy to populate. Orcs and worgs can be the main enemies approaching the lair. Staying thematically appropriate on the approach is easy, and mutable, depending on where the lair is. In a forest, ankhegs, ants, bear, boar (any real world creature appropriate to the terrain, really), goblins, ogre or owlbear all make thematically appropriate encounters. Adjust accordingly for swamps, mountains, or desert.
While flipping through my monster books, two creatures stood out as particularly interesting to place on the journey to the tablet: brownie (yup, the fairy) and a giant rock weasel. The brownie could be a helpful NPC to guide the party in the correct direction. And the giant rock weasel (Monstrosities, 398) is an excellent foreshadow monster. "Rock Weasels are Giant Weasels that have come into contact with potent transitive magic, becoming attuned to the elemental earths." (Monstrosities, 398,  Andrew Trent, Author)

The mythic underworld of the orc shaman appears straightforward. The elements are so thoroughly covered in D&D (and clones) that it's pretty easy to find monsters and ideas for the dungeon. Breaking into the cavern, the PCs find a fairly normal tribe of orcs. Dealing with them leads to a broken wall, which a few rust monsters live inside. The rust monsters were some of the latest creatures to answer the call of the tablet. Moving a bit deeper, we find a few hill giants, who are displeased to be answering a call from an orc, but are loyal to the master of the tablet. Deeper still, we can add any of the following: bulette, gorgon, medusa, roper, piercer, stone golem, and eventually coming face to face with the orc shaman, and the newly formed earth elemental.