One of the main factions in Warhammer 40K, the Eldar (stylized as Aeldari) are a highly-psychic, elf-like race whose history stretches back millions of years before the current setting. Once the most powerful empire in the galaxy, the Eldar would fall to unprecedented decadence and corruption, resulting in the formation of the Chaos god Slannesh and the fall of their empire (and with it, finishing off humanity's already-weakened pre-Imperial government, starting the Age of Strife). A few would survive aboard massive Craftworlds, having seen the impending fall and evacuating ahead of time. The Fall, however, continues to haunt their species, as Eldar who die and whose souls are not transferred to a special Soulstone are instead consumed by Slannesh.
In recent editions given the increased threat Chaos poses to the galaxy, some Eldar groups have begrudgingly cooperated with the Imperium of Man, given their common enemy.
