The good news is that it looks like it will be soon! We noticed new builds up on Steam using the lovely SteamDB entry for it, so we hit up the developer who gracefully replied:
@gamingonlinux It's in the (hopefully) final QA pass! ;)— Leszek Godlewski (@TheIneQuation) September 8, 2014
He also confirmed it's just Darksiders for now, but Darksider 2 will be a bit further off as he's only one man. Big thanks for replying Leszek Godlewski! Someone send him cake.
There's masses of big games coming to Linux in the next month or so like Tropico 5, Darksiders, Borderlands 2, J.U.L.I.A.: Among the Stars, Shadowrun: Dragonfall - Director's Cut and many more!
Are you excited? All aboard the hype train choochoo!
Deceived by the forces of evil into prematurely bringing about the end of the world, War – the first Horseman of the Apocalypse – stands accused of breaking the sacred law by inciting a war between Heaven and Hell. In the slaughter that ensued, the demonic forces defeated the heavenly hosts and laid claim to the Earth.
Brought before the sacred Charred Council, War is indicted for his crimes and stripped of his powers. Dishonored and facing his own death, War is given the opportunity to return to Earth to search for the truth and punish those responsible.
Hunted by a vengeful group of Angels, War must take on the forces of Hell, forge uneasy alliances with the very demons he hunts, and journey across the ravaged remains of the Earth on his quest for vengeance and vindication.