Elves. A word that evokes a strange mixture of contempt and admiration in most humans. They were the rulers of this continent where the human race now thrives. Before the Great War...
IMC, elves have gnome statistics and are a different species from humans. They have the role of elves+dwarves+gnomes. They are inherently magic. They don't have to learn magic, they just tap into the Weave itself, in a mostly sorcerous way. This means, scholarly wizards are humans; humans were taught magic by the dragons of their home continent, who let their slave race have a glimpse into this art, until the dragons got bored. Elves get slightly older than humans (120 years), but humans think they are immortal, because elves don't bear the marks of ageing in their somewhat exotic faces.
Elves don't like the burning light of noon or wide open spaces. They are the creatures of dawn and dusk, and that's why they did not really take notice of the advent of humans to the southeastern dry steppes with the great river, where the oldest empires of humankind in the new world were founded. When the elves finally decided to eradicate humankind from this continent, it was too late. Ill planned battles born from the elves' hybris led to their defeat. The most advanced elven nations crumbled to dust and made room for a large human empire spotted with ruins of their elven predecessors. At the same time, this led to their second defeat by the trolls/orcs/goblinoids (the third species on this continent, built from traits of all of the D&D races mentioned, living in the North).
"Today" there are five large cultural groups of elves IMC. In the hilly south of the "Spine of the World" (a large mountain range reaching from the southwest to the northeast of the main continent) live one group of elves. They are bit smaller than their northern cousins and are mostly nocturnal nowadays, although they also loved the twilight in better days. They have to hide their dwellings under the hills, because the southern human nations still have bounties on elf scalps, and discovered elvish settlements will be treated with alchemist's fire. They live in small villages led by a committee of elders.
These elves represent also a sizable minority in the oldest human city on the continent in the southeast, a large port city. There they can be seen with their gigantic hats (think vietnamese) with colourful veils falling down from the edges of those hats. This protects them from the brutal daylight - and from recognition
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Underground canals lead from the villages of said elves to the large open mountain lake that feeds a gigantic underground river that in turn builds the foundation of the society of "dark elves" under the central "Spine". They are definitely no drow, but just elves of the dark realms. They have white skin and are very reclusive, just trading with their southern relatives via the Grand Canal. They have the highest civilisation of the recent elves with city states at underground lakes. They breed a special demi-intelligent goblinoid slave race that works for them.
The large woods of the west harbour an elvish society reminiscent of the "King under the Mountain" of Tolkien's "Hobbit", though in numerous copies. When the Great War vanquished their more civilised relatives, these elves were reluctant to try their fate by battling their new human neighbours. On the other hand, this western human race (one of the five big human races on this continent) chose not to fight their elvish neighbours, either. This lead to a development of humans and elves side by side, without too much contact. This changed when the great human Empire that replaced the eastern elves tried to conquer this land. Elves and native humans together managed for their homeland to become part of that Empire in a peaceful way - but on their own terms, preserving their traditions. Since those times elves and humans have been on good terms in these lands.
The North is the land of the trolls (orcs), with a few human settlements. It's also the land of primitive elvish tribes. However, here the elves are but a shadow of their former abundance. They don't really play a role.
In the very west, the last city of the former elvish rulers lies at the shores of the western ocean. Here, the old traditions live forth with the descendants of the last refugees from the Great War - and with them their old hatred of humans. However, the bulk of the nation descends from primitive elvish tribes that never took part in the human/elvish rivalries, so there is not a big threat going out from that city.
The last larger elvish culture can be found under the fiery volcanoes in the snowy north east of the continent. They are the great smiths working in the forges with their molten raw material. Those elvish kingdoms have a good relationship with their human neighbours and hate the trolls and their own dark elf kinship, because the latter had driven them out of the central "Spine" ages ago.
As humans and elves are different species, there are virtually no half-elves IMC. Usually, there is no offspring at all from a union of an elf and a human, or it's born dead. The only exception are three sterile survivors. These are great oracles, slightly insane and living in the west. They are guarded by fey. Speaking of fey...
Although elves don't get even nearly that old as PHB elves IMC, there is one way around this. An elf can make a great gift to his community or a special individual. In a difficult ritual, they can become a fey, a protector of a certain cause. This will extend their lifespan by at least a factor of ten - but for a price. Although they will always remember their agenda that led them to become fey in the first place, they will forget family, friends and their old life after some time. Sooner or later they will lose most of their free will and personality, until they will eventually slip through the gates of the Plane of Shadows, where they will virtually live on forever, excluded from the great gift of death and afterlife.
