Elves do not die of old age. They can be murdered, however, and are susceptible to most diseases. These last two facts are why humans have been able to wrest control of the world from elves in the last few hundred centuries. Nevertheless, there are elves who count among the oldest living things in Oris, and with such vast amounts of time often comes knowledge, power, and opportunity. The most powerful among such elves are known as High Elves.
When you hear High Elf you pretty much get the picture on what I'm talking about, powerful immortals with wide spread influence or power, probably magic users, etc. Their intellect is far sweeping and their machinations unfathomable to the mortal brain. The only real difference between my high elves and most is that it's not really a race, more of a choice.
To be a High Elf is to insert yourself into The Game, which I keep talking about and will get into sometime. Basically it's a war between every long lasting immortal, dynasty, secret organization, and even every idea on the planet.
High Elves have wide-sweeping, century spanning plans, their conflict between each other is both very clandestine and very orderly. Political and institutional warfare, puppet rulers behind puppet rulers, spells and rituals on a massive scale but a slow, subtle pace. As long as they play their cards right, they will be there when everything else is not, so then, should they not be entitled to shape what is rightfully theirs?
Most elves never survive to be high elves. Some do, and choose not to. Some have the same level of power, knowledge, and experience required, but become Low Elves.
The Low Elf is the complete rejection of The Game, of society, of existence. The Low Elf is the Dada artist, the gonzo journalist, the nutter living in a barrel down the street from you who can kill you with a look.
While the High Elf seeks to rule the world, or unfold some grand scheme, Low Elves seek artistic fulfillment, esoteric experiences, or just pure hedonistic pleasure. Low elves exist in complete rejection of policies, rules, and purposes of their brothers and sisters. Immortality has not given them purpose to shape the world into a place that they see fit, instead it has made them bored, and they're gonna get real weird with it. I think this is really what the difference boils down to, the question of; "If I live forever, what do I do?"
Both types of elf can be excellent allies or quest givers to a party, as well as antagonists. A Low Elf might be a fun guy at a party, paying for a new kind of psychedelic, or a journalist seeking to upturn a regime. They also may be a serial killer, or a wizard who wants to decimate a town for aesthetic purposes.
Occasionally, low elves can have as wide-sweeping influence and plans as a High Elf, and the difference between the two is sometimes impossible to spot, it's really just a matter of branding and intent.
High Elves fucking hate Low Elves.
Low Elves mostly don't care what High Elves think. Those that do find it hilarious.