Ereshkigal Forest
Ereshkigal Forest, known to locals also as The Great Forest, is one of the several existing Outer Realms of the Hexarchy, as of 1686 AN. The forest itself is considered to be one of the single most hostile places to civilized life on Micras, and the people of The Hexarchy have taken measures to ensure that the forest continues to become simultaneously self-contained, self-sustaining, and ever-hostile to undesirables placed into its dark embrace. Named after the native Goddess of Death and the Underworld, the place is a fitting location to deposit criminals otherwise sentenced to death for their crimes. Since killing another person is illegal there, the inhabitants instead cultivated a specific place hostile enough to guarantee that the job is always done for them, thus breaking the cycle of human-centered violence within their borders.
Geography
The Great Forest is a vast jungle rainforest that is located on the country's southern interior. Divided from the River Lands by hilly terrain and shallow soil, the land is nonetheless abnormally fertile for being unable to host the vast trees endemic to the jungle itself. The small portion under nominal control is completely undefended except by surface-to-surface missile systems, in case the otherwise balanced ecology (as dangerous as it is) acts against the developing agricultural settlements on the River Lands to the north and east. For reasons unknown, almost none of the more vicious predators in the jungle ever move past the very well-defined tree line about forty to fifty kilometers from the River. Thus, agriculture has rapidly developed in recent times. Due to the extreme danger posed by enter, the portions under Hexarchy control have become known to local cartographers as Ereshkigal Forest -- aptly named after the Pyraxian goddess of death.
The Great Forest is mostly uninhabited due to the terrain and the dangerous fauna. For the latter, the wildlife is constantly added to, as the vast area serves as a convenient dumping ground for dangerous animals smuggled into the islands. Alternatively, the government has been known to experiment with sending certain animals such as the Jingdaoese valleytiger into the forest to see how it interacts with the other, much larger predators in the region. These constant activities also serve to deter any unwanted persons (mostly prisoners serving on the collective farms run by the Elamite government) from escaping into the forest. It also deters illegal immigrants and poachers from entering the forest except as a part of a specialized hunting expedition. And even then, those expeditions flying in from Pyrax tend to leave the jungles alone due to their vast trees hiding both prey and predator alike.
Defense & Maintenance
Thus, defensive responsibilities of the Great Forest fall to the collective military efforts of Elam and the Eventide Islands, along with their subordinate Realms and Districts. Despite the extremely dangerous terrain, control over the vast jungle has been partially exerted over a stretch of land surrounded by the Great River and Red River on two sides, and bounded by a fortified coastal region under the firm control of the Eventide Islands' paramilitary forces.
The fortified portion is nominally occupied jointly between these realms relies on the River Lands' districts for day-to-day governance, while overall authority is vested in the Council of Six (although, due to lack of permanent human activity, is moot). Although the forest itself cannot be defended due to the recent addition of wild dragons by the Pyraxians during failed expeditions, conquest has been rendered impossible. On the upside, neither can neighbors reasonably occupy the forest, due to the Hexarchy's control of the only civilized areas bordering it.
The primary interest of defense authorities is the segment of the Pan-Keltian Highway that runs along the coastal roads south of the forest. A very slender land corridor on the south of the forest was successfully fortified from 1695 AN, allowing the completion of one of the most well-guarded roadways on the planet. The road was completed not long after the official annexation of the East Bank Territory into The Hexarchy was enacted, completing the connection from New Alexandria's land border to the western parts of the Hexarchy's domains.
Minor instances of creatures escaping from the Forest do occur on rare occasions. However, no fauna escaping has been large enough to pose a threat beyond roadkill hazards to passing traffic, and such incidents are usually settled within minutes due to the proliferation of guards and defensive infrastructure that runs along the 300-odd kilometer stretch of near-unbroken roads. The only rest stops are fortified, although very well-provisioned for travelers.
Science
The region is a special case worldwide as far as open air environments of this extreme degree of competition for survival. Predators have shown to have grown more intelligent, fiercer, or stronger over the years due to the sheer intensity of natural selection occurring due to constant additions to the closed region. Proposals have been fielded to import some of the giant bugs that periodically threaten the island of Drag'os, but such proposals have been shut down due to the bugs' violent nature and extreme rates of reproduction making management impossible with current infrastructure.
This vast, closed environment has provided models to other nations proposing to send astronauts to Tarsica in the future. Even though the jungle has an extreme pressure on species to survive intense predation and cannibalism, it shows that life is extraordinarily tenacious, and that humans may have a chance of permanently settling the moon beyond a couple hundred inhabitants.
Tourism
There are numerous flights that go near the edge of the forest, although not above as commercial flights are strictly prohibited. However, some privileged few can visit one of the many forts that surround the vast enclosure to catch a glimpse of the truly fierce wildlife that inhabits the area. If one is lucky, they get to see the many native and introduced forms of wildlife in action.
Executions
For those with a sadistic mindset, banishments to the forest (which replace an outright death penalty in the country) are done on a predictable schedule. Unfortunately for those who come to see such events, attendance numbers are harshly restricted due to the country's aversion to putting human cruelty on such shameless display, and to avoid humiliating already-fearful convicts who would otherwise be able to prepare themselves for the end.
Instead, human rights groups and policy leaders typically bear witness instead. They record the execution's proceedings, and ensure that no direct killing of humans by other humans is involved at any stage of the process. However, convicts are sometimes given drugs that make the end painless, if any are there to vouch for the condemned. Human rights groups sometimes condemn the Hexarchy's haphazard way of instituting their indirect death penalty, as some predators in the jungle are far less efficient killers than others, and the one that gets to the condemned is always random.
Survivors & Criticisms
Only three documented cases have emerged of condemned persons surviving the harsh nature of the jungle, of which only one has successfully braved the odds in a trek to the other side. This individual, named Ardashir Marducherib, had his sentence commuted in late 1704 AN as a reward for his incredible resourcefulness and obvious favor of whatever god was responsible for turning predators' eyes away.
It was also found later that, although he was guilty of certain crimes, the one that led to his sentence of banishment to the forest was manufactured by the very judge that sent him there, after he was bribed by a prosecutor with a financial stake in the matter. Later investigations found that, while no other persons sentenced to death by banishment to the forest were innocent of the crime that merited such extreme measures, the justice system in the country was nonetheless rife with corruption. As such, executions in this fashion have fallen more out of favor, and life imprisonment or banishment to a willing recipient country have instead slowly started to take over as favored life-term punishments for the accused.