Sanity is relative.  We should call them "rationally challenged."

Why are they called "The Fallen", anyway? Fallen is usually a derogatory term associated with degeneration or devolution of one form or another. Wheras these fallen, in the world of Elemental, sounds more like Ascended beings, superior to the average mortals they share the world with.

What does the snake, dog or cattle matter to humans? And as such, what does the humans matter to us that have ascended, or transcended, our flawed coil? No, I tell you, we are the peak of human evolution and magical intricacy, chained only to boundless potential!

The humans vie for our power, like jealous little siblings, mere children, in the face of the eldar gods. Like naive and pathetic creatures bound by the human condition they call us "evil", "oppressive" or "insane". What is insanity, if not to willingly grovel at the feets of creation itself, spitting acid and foul words at their betters?!

Bah, I say! Bah, and woe to "humanity" and all the little, small-minded creatures of this world!

They seem like a bunch of fascists to me. Productive - but not creative - masses.

The name "the Fallen" has more of a religious clang to it, like they have forsaken their gods or something.

https://www.elementalgame.com/fallen.asp

When the powers strove for dominance before the cataclysm, some felt that men were too random and too unpredictable to be of use to them. Some of these powers selected men of cunning, brutality and might. They created an “improved” or “idealized” version of men that came to be known as the Fallen.

The Fallen are stronger, faster and more lethal in battle. They are quicker to make use of magic whenever available. The fallen are consistent, patient, and considered all together evil.

The Fallen do not embrace change well nor do they appreciate new technology or the value of community. The strongest thrive and the weak are eradicated.

One could also argue that their inability to embrace change inevitably makes them and inferior race (from an evolutionary stand point). Despite being stronger, faster, and more adept with magic, being unable to adapt to change is a large weakness in the long run.

Indeed, that's a pretty solid idea for what they are. I think are alot more Hive minded than human, as In they care allot less about individualness.

It was never argued that they can't change, just that they don't embrace it. Most animals don't embrace change, and change because they have to. One (important) aspect of Evolution is to continously weed out those that fail to adapt. You don't see too many monkeys trying actively to learn to swim, but if their habitats are flooded, they bloody well have to learn pretty quick!

Drow ? As far as i can see these are former humans, selected for some traits and then empowered in different ways, so while they are physically stronger, they are a bunch of bastards not able to work well together Not sure if there is something to compare them to.

A bunch of fanatical bastards, and i do believe they possess some ability to work together actually. In any case the fallen were altered by some greater power, i think the drow just ran off like the sissy elves they were

Of course a more intereting question would be, how do the 6 factions play into this ?

I think they should be implemented as a more orderly evil race (although I'm biased, since I hate playing the forces of chaos), akin to the Lawful Evil D&D alignment. The "Let's burn the village and take all the women!" kind of evil should probably be left to the Beasts. Or, now that I think of it, there could be multiple factions of Fallen, just as there are multiple factions of Men, and these factions could range from the heartless efficiency and unforgiving disclipline of Orderly Evil to "ends justify the means" Pragmatic Evil to the aformentioned Viking raider style Chaotic Evil.