I don't know the whole history of Greyhawk, but it sounds as if you have invented much of this history yourself for your world or based on your past campaigns.
Starting just after the Greyhawk Wars, which are canon, it changed from canon to a house setting as I altered history. For example, Greater Ahlissa never became the successor nation to Aerdi, which is the canon.
I stand by my original post concerning most elves in a normal setting. It is clear now that you are not talking about a normal setting.
Then pity the elves of Krynn, Toril, Oerth, and Athas, for theirs is a sad lot.
The only reason any of them are still alive is mainly because humankind (and many other powerful races) simply haven't decided to exterminate them yet, or because humankind (on Krynn and Athas) simply hasn't quite yet finished the job of extermination.
If that is normal, and I would guess the official settings would describe themselves as normal, then take pity on the elves!
And no, the elves retaking Cormanthor does not mitigate what I've said.
The elves have retaken Cormanthor. If any strong nation or group (Cormyr, the Zhentarim, etc.) wanted them back out of Cormanthor, out they would be. If Myth Drannor could not withstand the grand events, these pathetic few won't do so.
In this case, I can't really even comment further because I don't have the knowledge of your world or your elves or the numbers and classes and levels of the surviving elves. If you are looking for a way for the elves to survive under these conditions, then I would need to know the lay of the land, the surrounding lands, relations with the surrounding lands, what exists for natural resources, exactly what they currently import and export, how many elves are in the forest, how many clerics, fighters, mages, rogues, npc classes, etc., what creatures and animals dwell in the forest, what levels, who is their leader, what allies they have, what current enemies., you get the point.
I have given a great deal of it's history, but I admit I can't flesh it out in this thread.
There were 325,000 elves in Delrune. Delrune was 100 miles north-south, 75 miles east-west, for a total of 75,000 square miles.
98% of the elves of Delrune lived in cities (Archendrea, Miralea, Delphea, Starleev, Harpmotes, Lirrendrea, Kindlerock, Sunleai, Haldendrea, and others) with an average population density of 5,000 per square mile. Thus, these cities occupied around 65 square miles of Delrune.
2% of the population lived, with permission from the authorities and the blessing of the Faerie, within the forests.
A large Faerie population of over ten thousand existed within Delrune, along with a large population of magical beasts and animals of good and neutral nature. (Yes, the rare unicorn rider occurred.)
Forests covered 80% of Delrune. Of the remainder, most was natural meadowland (trees would not grow in the northwest, for unknown reasons) and a sizeable centaur population lived there, under the rulership of Delrune.
Delrune was hilly, with the hills slowly rising into the Clatspur Mountains on the east side, the range running north-south and protecting Delrune from attack in that direction (Archendrea guarded the one pass through, and Chauntosbergen laid claim to, and protected, a great part of the range south of Archendrea.)
A range of mountains rose in the north - running east-west but falling swiftly into the lowlands of Calrune on the west end, and these were the home of several groups of marauding giants. Wary of these giants, the elves created a defensive line of watchposts and manned them. But attacks were few and far between. The Greyhawk Wars saw a sharp attack into Delrune by these giants, but they were stopped before they did much damage, mostly by the actions of the Faerie. No passes existed through this northern range.
To the west and southwest of Delrune lay a large lowland, the valley through which the river that drained Lake Quag came meandering south. This was the realm of Calrune, a partially grain intensive human society, partially centaur society, and partially merfolk society (living in a lake in the midst of the realm.) Calrune was extremely friendly to Delrune, no border existed in any real sense, and trade was heavy between these nations, especially since Calrune imported in vast amounts of goods up the river from the Nyr Dyv through Furyondy and Swantmoor. Around 100,000 humans, 5,000 centaur, and 10,000 merfolk lived in Calrune. Very little forest existed in Calrune, having been removed for grain crops long ago.
To the south of Delrune, the hills gave way to small hillocks and rolling land. This was Swantmoor, a gnomish nation. The gnomes were also friendly to Delrune, and no distinct border really existed. The gnomes, living in underground burrows (far larger than halfling burrows) were glad to expedite trade, while shielding Delrune from Furyondy. Several tens of thousands of gnomes lived in small Swantmoor.
In the mountains east of Delrune, as mentioned, was Chauntosbergen, the great underground dwarven city and civilization. It went over 10 miles down, and spread across the surface up and down the mountains. These good aligned high dwarves were on peaceful terms with Delrune, but rarely visited (and the elves rarely visited Chauntosbergen.) Travellers were welcome, but the elves and dwarves looked upon each other's cultures as being unpleasant, respectively, so they did not stay long.
Chautosbergen was an important exporter of raw metals and raw precious metals to Delrune.
Chautosbergen had 25,000 dwarves living in the city, and 50,000 more in the surrounding mountains and Below.
Incidentally, east of Chautosbergen was the Vesve Forest, and it was as per the canon.
In total military terms, if Furyondy rated a 10, Veluna an 8, Gran March a 3, and Bissel a 2, then:
Delrune = 2
Calrune = 2
Swantmoor = 1
Chautosbergen = 4
The climate of Delrune was magically created, through the efforts of the Faerie who lived there.
The climate was warm temperate, with long warm summers, short cool winters, and distinct seasons. Highs and lows averaged in the 70s and 60s in summer, and in the 50s and 40s in the winter. Frost and snow occurred during the winter, and gentle rains and the occasional heavy rain and thunderstorm occurred in the summer.
The moderation extended to Calrune, in lesser form: summer highs and lows were in the 80s and 60s, and winter highs and lows in the 40s and 30s. Snow and rain occurred in the winter, and heavy thunderstorms in the summer.
In the mountains east of Delrune, summers were marked by violent storms, and winters by blizzards. Temperatures were moderated as per Delrune, but fell with elevation.
In the mountains *north* of Delrune, the climate quickly grew chilly as you proceeded into them, with short cool summers and long, cold winters. Summer highs were in the 70s and lows in the 50s, and winter highs were in the teens and lows near 0. This was in the hills; up at high altitudes it was far worse. Heavy snow fell in the winter, and terrible violent thunderstorms in the summer.
After the Greyhawk Wars:
Only a few thousand elves out of the entire population of Delrune were classed as adventurers (core PHB classes.) The rest had NPC classes, almost universally under 10th level.
Fighters were generally 1st level. A very few were 2nd level. A rare handful were 3rd, 4th, and 5th level.
Rangers were few, and generally 1st or 2nd level. A very few ranged up to 5th level.
There were 3 or 4 paladins, of moderate level (around 6th.)
No barbarians existed in Delrune, amongst the elves.
A fair number of clerics existed, with levels up to 5th. A handful of clerics existed, with levels up to 7th. A couple were 8th level. The highest was 9th level.
A large number of neutral good druids existed, with levels up to 5th, and a few up to 9th level. Almost no true neutral druids existed, and no neutral evil druids.
A large number of wizards existed, with levels up to 5th. A few were up to 7th level. A handful were up to 9th level.
Bards were the most common adventuring class. More than half were 3rd level or higher. 5th through 7th level was common. A few had made it to 10th level.
Very few monks were in Delrune. These few ranged from 1st through 7th level. No monkish orders existed, and elves who left to become monks never returned to Delrune, as a rule.
Delrune imported, among other things: finished swords and armor, raw metals, raw precious metals, timber, foodstuffs based on grains and a number of specialty foods and drink, wine (the elves did not make their own; unusual for elves), papyrus and parchment, ink, leather and leather goods, rope, tapestries, objects of art, books or copies of books, and so on.
Delrune exported, among other things: Crystalline items (described in a prior post), magical scrolls and potions, copies of books, copies of poetry, wooden furniture, wooden art and decorative objects, wooden lighting items, musical instruments made of wood and metal, statues (of crystal rock or other substances), worked gemstones and jewelry (in very small amounts), specialty items from the forest (rare), specialty items from the Faerie (very rare, and very valuable, and traded only with permission and to friends outside Delrune), clothing of all types of a substance unique to the Delrunian Highlands and uniquely elven made, glass and glass products (including windows and installation, which was priceless), mosquito nets and woven nets of the same substance as clothing was made of, and so on.
The 98% of the elves living in the cities lived, for the most part, in great crystalrock towers that rose above the trees, often connected to each other by abutments, ornamental and aestetic in nature, with the natural world all around. Great openings abounded, along with glassed windows. Ornamental, multicolored lights of a magical nature lit up the cities, so there were visible for many miles (astrologers and astronomers, the elves were not.)
Many generations of a single family lived in the great towers. An inhuman level of closeness, lack of privacy, and cooperation and harmony existed. Crime was rare (thieves were subject to reorientation (gentle brainwashing)) and murder almost non-existent (when one did occur, if the assassin was caught he was sent to the Faerie as punishment, and rarely ever came back.)
Travel was by the surface and by skyways. Commerce was paramount, although elves varied immensely in how long they worked, or how hard, and even more in how good they were at creating items. Celebrations and festivals were common, occurring at least weekly. Religious services occurred weekly.
An immense amount of total time spent, was spent in the raising of children. Children were prized above all other things, both by law and by elven nature. Elven parents doted on their children, were gentle, were patient, protected adolescents from themselves as they could (the authorities *gently* worked with them on this), and otherwise fought to be the best parents they could be. Child abuse in the normal sense was unheard of.
Women were prohibited from fighting (they could hold office; ignore my earlier comment on that.) Women could become fighters or mages or any other class; they simply were not allowed to use those skills to fight.
The elven women of Delrune were accustomed to this law and never questioned it.
The King ruled over Delrune, in a benevolent dictatorship. Working with him were his advisors, and his Queen.
Under them were the elven families entrusted with the rulership of Delrune's many cities. (Ownership of land was not a relevant factor, and wealth did not bring power nearly so much as in human societies, so true nobility did not exist.)
Under them was a small force of people designated as what we would call law enforcement. The small criminal justice system of Delrune was composed of these elves, and the ruling families would judge if requested to, or in special cases.
A large governmental bureacracy did not exist. For the most part, elves were self-governing and the cities independent.
Taxes were judged a human institution and unnecessary. The King raised money through his own trading company, in essence putting him in competition with his own people.
Service in the army was voluntary. The level of discipline and effort required to be in the army was quite small compared to anything demanded of a human soldier. Volunteers typically had little discipline, little fortitude, but strong morale (as they were fighting for fellow elves.)
After the Greyhawk Wars, discipline and effort increased greatly, as Delrune attempted to field a respectable army. Their efforts paid poor dividends, however, despite a fair number of volunteers.
The culture of the centaur people involved a very loose government bowing to the King of Delrune, and their own way of living. They rarely intermingled with the elves.
The culture of the Faerie varied from race to race, but all paid homage to Oberon and Titania. They were nominal subjects of the King of Delrune, but in effect were independent.
The 2% of the elven people living in the forests, often visited the Faerie or worked actively with them. Many others were students of the natural world. Still others were on personal quests involving travel and interaction with strangers. A few were Watchers on the borders.
Calrune had a cosmopolitan culture similar to Renaissance England - under a strong King - except far less harsh for commoners and middle class alike. Calrune was constantly full of merchants, visitors, and the occasional envoy.
Unlike Delrune, Calrune maintained a strong, disciplined army (their wealth through trading made it possible) and a strong secret service. Their secret service was experienced and well travelled, and worked hard, since Calrune was filled with agents from other lands.
Calrune considered Delrune an indespensible (if incomprehensible) source for certain goods and services, and the policy was to 'protect' the elves.
Calrune also considered Chauntosbergen an indespensible source for metal, and the trade routes went through Delrune. Ensuring the well-being of the elves was paramount.
Swantmoor had a bustling and relatively cosmopolitan set of cities, composed of mines, burrows and aboveground buildings. Production of items of all manner was the norm, and life was fast and busy (and occasionally uproarous.)
A small army existed, partially to aid Furyondy and partially to protect *from* Furyondy. But during the Greyhawk Wars, Swantmoor was threatened by Iuz to the east, and a large army was raised. Iuz did not attack and fell back, and Swantmoor turned it's new soldiers to the production of war materials. Food shortages occurred, and a major effort had to be made to clear the land for farming and produce underground farms.
A ruling council governs Swantmoor. Their decisions are passed on to the local level. The pre-war beaucracy has been replaced with a more martial system, due to necessity and hunger.
Chautosbergen consists of a single large dwarven city, and a number of smaller towns connected by tunnels (roads) to the main hub. Great mines extend outward and down. Surface settlements are military in nature.
Chauntosbergen is dwarven, and martial. All dwarves are trained in warfare, a large force of clerics is readied, but the dwarves are lacking in wizards (they are attempting to learn, but few seem to have much aptitude for it.)
Great underground farms and cattle ranches exist, well protected from attack. Great smithies and forges in the main hub produce an unending array of weapons, armor, and items of necessity. Prior to the Greyhawk Wars, far more peacetime goods were produced, but now few are, and life has grown more austere.
The dwarves actively participated in the Greyhawk Wars, helping to hold the southern Vesve out of Iuz's reach, building military bases throughout and under the mountains, establishing scout perimeters above and within the Clatspur range and in the Vesve, and establishing mutual defensive treaties with Delrune, Calrune, Highfolk, Veluna, and Furyondy, as well as the peoples of the Vesve.
The dwarves, as a result, have a fair number of fighters between levels 5 and 9, and a few between 10 and 14. Some of their clerics exceed 10th level.
The dwarves consider the elves of Delrune to be children to be protected, and protected from themselves if possible. They are condescending, but hide it well enough.
You are not looking for a justification that elves are destined to die in a regular setting as first believed, you are asking, how can these elves in my home-brew world survive because they got screwed by war?
Because they were caught up in events not of their making, events not of their choosing, and certainly not of their liking, but caught up nevertheless.
And escape was not an option.
The elves of Delrune found the world crashing most rudely into their sheltered world, and there wasn't a thing they could do to stop it. After the crashing stopped and half of them were dead, the rest fell apart.
They simply could not cope with it. Their society collapsed, government failed, and terror prevailed. It lead to evil rising in Delrune, elves turning to the darkness, elves lured by Lolth into her service, the Faerie abandoning their former friends and allies to their fate.
For 20 years Delrune languished in semi-anarchy, torn apart by rival factions worshipping conflicting powers, while some uncorrupted elves and a very few Faerie tried to turn things around.
Then Vecna came, and no power the elves possessed was sufficient to save them, and Lolth's power - like Lolth herself - proved it's irrational uselessness.
