Character: It's hot down here!
The Caves is the third set of levels in Diablo I, consisting of levels 9-12.
There are no Shrines, but barrels do appear. Walls and doors are replaced by fences and fence gates, and many monsters can open the gates.
The levels are rocky, natural environments populated by more hellish monsters, many of whom spit acid or lava at the player. The areas are frequently blocked by convoluted lava flows, but the levels are generally wide open with death around every corner. A small step in one direction can lead to packs of hungry enemies bearing down on the player. Stairs to the next level appear as square holes in the rock walls.
As with other level sets, the first level of the Caves, level 9, has a staircase up to town. The entrance is a hole in the cliffs near Wirt. Mousing over it says "DOWN TO CAVES".
The Caves has two singleplayer-only quests. One or both will appear in a given singleplayer game.
Both quests share a quest group with Zhar the Mad, such that at least one of the two will appear in a given singleplayer game, with a 1 in 3 chance of both appearing in the same game.