A long-extinct race of greater beings from whom humans, their language, and magic descended

"Ahrendas" The Beginning,
"Axides" The End

Unknown.(Fairly tall, though most humans today would be considered taller than them.)

Unknown (Varies depending on height, lifestyle, and genetics)

Red eyes, which are depicted by rubies. Most statues and murals are missing the eyes due to theft. (Red eyes with black/dark grey sclera, white or very pale hair, pointed ears which sometimes shows up in humans as a birth defect, able to control magic like it was made for them without any of the detrimental effects it has on humans.)

Not much? (A lot, Elven were spread across the landscape and adapted accordingly.)

Scant, with finely woven fabrics printed in both bright and neutral colours. Used copper for jewellery. (Highly elaborate clothing based on rank within society, how wealthy the elven in question and their family was, what gender they wanted to present as, and their marriage status.)

Unknown, remaining depictions are in copper or stone. (Varying shades of brown, leaning toward darker shades.)

Most depictions are of thin, sharp-looking males. (Varies depending on lifestyle and genetics.)

Knowledge of architecture, magic, and warfare. (Lived nearly three times as long as current humans due to magic enhancing their lifespan, were knowledgeable on building aqueducts, roman concrete, and other innovations until they were lost to time, were able to destroy areas completely during war - some swatches of land are still unusable thousands of years later.)

Unknown. (Fragile immune systems, devastatingly reliant on magic, probably suffered from copper poisoning.)

Not much is known about the Elven, for much of their magnificence, architecture and written work alike, is lost to time. Humans know, theoretically, that something big happened to make the switch from Elvan to human and, though they're fairly certain they descended from them, they don't know how.

(Elven were a pretty populous and influential race to the history of the world, with several notable wars and sieges remembered in oral traditions and nonsense nursery rhymes, but as it wasn't written down scholars are unsure as to what happened and where. They fell through a combination of widespread drought, disease, and rebellion by the humans of the time, though that fact - coupled with the few undestroyed artefacts left behind - has been lost to the thousands of years between then and the present day.)