Deep Cthonic (DEE-puh kuh-THAWN-ik)

The Deep Chtonic is the overarching (better yet underarching) term for the tunnels, caverns, passageways, underground rivers, and such that span below the surface of the Leitan Peninsula.

Regions of the Deep Cthonic

Topside - The name that inhabitants of the Deep Cthonic use for the surface of the Leitan Peninsula.
Top Cthonic - The Top Cthonic exists from just below the surface of the Leitan Peninsula to approximately 3 miles below the surface. Most surface explorers never journey below this level of the Deep Cthonic. It is a chaotic region; a frontier between the surface world and subsurface world. If a conflict between two world is going to happen, it will most likely occur here.
Meisalcthonic or The Meisal -This is the region of the Deep Cthonic that lies between the Top Cthonic and the True Cthonic. Three to ten miles beneath the surface of the peninsula. This is where true residents of the the Deep Cthonic dwell and rarely leave.
True Chtonic - The True Cthonic is 10 miles or more below the surface of the peninsula. Very few entrances or exits exit to this truly horrible realm.

Environment

The Deep Cthonic's environment varies vastly from the surface of the peninsula. Adventuring and exploring it is a dangerous expedition. Similar to a desert expedition, adventurers braving the Deep Cthonic's many passages and caverns must be well prepared.
Very few locations in the Deep Cthonic have any natural sources of light except for the occasional luminous rocks or fungi. Large portions of it are also without food or water, requiring large amounts of food and water supplies for exploring uncharted terrain underground. Lack of light, tomb-like silence, and the posibility of starvation and dehydration makes traveling something only for the strong of will. The nerve-wracking silence makes even experienced adventurers grow agitated.
Similar to dungeons and tombs, the Deep Cthonic can contain stale and possibly poisonous air. It may contain explosive gases from underground volcanic activity or other deadly gases bubbling forth from deep fissures in the rock. Bad air and poisonous fumes can collect in portions of tunnels and caves more or less isolated from the main vaults and caverns. P-trap-like tunnels holding water could also trap these gases for a long time.

Ecology

Plant and animal life vary as much in the Deep Cthonic as it does the surface of the peninsula, ranging from small insects to human sized sub species or even as large as dragons, which set up their territory deep below in the cthonic. Expect anything and assume nothing. Plant life is unable to utilize sunlight for synthesizing energy, and take strange evolutions for their adapted life under the peninsula. Many fungi were also found underground. Being unable to digest normal nutrients most of the time, they rely upon miasmic radiation prominant in the underdark as a source of energy.

Climate

Temperatures in the Deep Cthonic vary with depth and proximity to geothermal phenomena. The deeper one travels into the Deep Cthonic, the warmer the air and surrounding rock. Occasionally, small, too small for the passage of most creatures, passageways open to the surface near cold areas on the surface and cool the surrounding air greatly. Throughout the year, the temperature remains stable and moderate in most regions, possibly slightly clammy and chilly.
The water underground is almost universally extremely cold. Immersion in it poses a great risk of hypothermia. Conversely some pools of water near geothermal activity are warm to hot. There are even some pools that are comfortable, but periodic venting of geothermal heat into the pool can quickly rise its temperature to the boiling point in very little time.