All the factions now have a shnazzy "forces of hordes" or "forces of warmachine" tome detailing all the particulars of history, fluff and including all the additional units since MK1. All factions that is, except for minions. They don't have tome yet, but when it comes out, I might be tempted to start GATORMEN. You'd probably want to take a gander at "forces of hordes - trollbloods" to get a good idea on the what's what and the Who's who.
In any case, if its a warmahordes game you a looking for, I suggest online play via the free programme vassal. Its all flavors of awesome.
Privateer press has created its own module for it and promotes its use, so its 100% legal. It has all the units from every faction available in the game represented by in game images that you can move around. Its got everything you need ingame: tape measures, templates, markers, you're-on-fire tokens, command range e.t.c
here's a screenshot of a skirmish between retribution and trollbloods.

Now, of course, fielding your own painted models on the tabletop would be preferable. But playing with vassal online, is quick and relatively painless. Further more it allows you to test ANY list you can come up with, and really fine tune your army until you know exactly which models you want to spend your hard earned yen on....like Karchev.
If anyone wants to try it out then Ennui or I can can find some time to log on sometime and have a skirmish.