So, the elves in Warmachine have the standard "We had gleaming cities and giant robots while you were still throwing rocks at each other" snooty deal, but it turns out they're not the elder race. In fact, they're knockoffs of humans.
The eight elven gods looked up from their immortal power games and saw that some other god (Menoth) had made humans in the mortal realm. They thought this was a pretty neat idea, and figured they could do it better, making elves. But where Menoth largely left his creations to struggle and die and work things out for themselves, the elven gods thought it'd be far better to directly teach their creations. So, something like 8000 years before the events of the game, the elves were building giant crystal cities and stuff, ignoring all the puny mortals around them.
But the elven gods took a lot of shortcuts in the process, leaving loads of hidden weaknesses that were papered over by active intervention. When an attempt to create a permanent gate between the mortal and heavenly realms blew up in their faces (the Babel myth of Immoren, basically), the gods were trapped in the mortal realm. Their power started to fade, and suddenly the immortal (except for death by violence) elves started dying of age and disease and stuff. Birth rates dropped, and every fix the gods tried was only temporary and made things worse in the long run.
Realizing they'd horribly screwed up and were weakening in the mortal realm, the gods set off to try to find a way back to the heavens...and then humanity was taught how to use magic and it exposed another glaring flaw in the elves: their connection to primal powers was like an unsecured wifi feed, and the humans started unwittingly choking all the bandwidth out. The elves were without gods and largely without magic (they only managed to keep one socket open in their connections to the gods), and the low birth rate was exacerbated by how babies were starting to get born without souls.
Meanwhile, Menoth's creations had pretty much taken over the planet, with only the occasional nudge from him and his fellow gods like Morrow and Thamar.
Elves: Immoren's version of a chrome-plated knockoff toy.