The subterranean level, or underground, is a gameplay concept in the Heroes of Might and Magic series. It was first introduced in Heroes of Might and Magic III, and allows a map to be split into two parts: one surface level, and one underground.
Usually, heroes travel between the two levels through the use of subterranean gates, but they can also use monoliths, or whirlpools. The adventure map of the subterranean level is always the same size as the surface, but usually, a lot of the space is not utilized, containing nothing but a black emptiness. Sometimes, both levels are filled with explorable land, and in a few rare cases, the subterranean level is actually more developed than the surface. The Regicide is a good example of the latter.
|Might and Magic game concepts|
|Character classes · Experience · Item lists · Monster lists · Party · Potion brewing · Trading triangle · Quests|
|Heroes of Might and Magic game concepts|
|Adventure map · Artifacts · Campaign · Combat phase · Creatures (I · II · III · IV · V · VI · VII) · Creature attributes · Damage · Dwelling · Experience · Grail/Tear of Asha · Growth · Hero classes (Advanced classes) · Heroes · List of adventure map structures (I · II · III · IV · V · VI · VII) · Line of sight · Luck · Morale · Primary skill · Puzzle map · Resource · Scenario · Secondary skills · Specialty · Spells · Subterranean level · Terrain type · Time system · Towns (I · II · III · IV · V · VI · VII)|
|King's Bounty game concepts|
|Boss · Heroes · Marriage · Spirits of Rage · Villains|
|Ardon series game concepts|
|Experience · Shifter forms|