If you were waiting patiently for Total War: Warhammer to finally make its way to Linux, I am glad to announce that your long vigil is now over. Through an update that came out a short while ago Total War: Warhammer has become fully available on Linux via Steam, so choose your faction and dive in!
However, if you've been waiting for so long that you've completely forgotten what Total War: Warhammer even is, Creative Assembly has prepared a rather handy video for just this occasion. Its not incredibly detailed, but if you're looking for a general overview its pretty damn good. Have a look:
As for the port itself, it was not made by Creative Assembly themselves, but rather by a third party - Feral Interactive. Even if the name doesn't ring a bell you've probably heard of them as they've worked on the Mac and Linux ports of XCOM 2, Tomb Raider, Deus Ex: Mankind Divided, Mad Max, and so forth. So while I haven't checked it out for myself, odds are good that Total War: Warhammer's port is a going to be a high quality one. And as an added little bonus, if you own the PC version of Total War: Warhammer you also own the Linux (and eventual Mac) version as well. So do make sure you don't accidentally purchase another copy!
And speaking of the Mac version, that one is still waiting for the all-important Metal update. As such, I'm afraid there's no release date available just yet, but I've heard multiple sources point towards the end of 2016 as a possible candidate. Whatever the case may be, I'll give you an update once it finally arrives. But for now have fun with the Linux version, because as I've noted in my review - Total War: Warhammer is a rather lovely game.