Factions 101

Factions at the base level are non player groups, each one is unique with different traits, they each have units and most have faction hubs/cities. Faction hubs are places where you can trade advanced goods (with a trader). Each faction has unique faction standings, not only with the individual but the race and other factions, these all determine how you are affected by factions and how you interact with factions. 

To start at phase one: http://elgea.illyriad.co.uk/#/Alliance/Faction -these are the factions in the game, 

On the left you see the faction names and which continent they are located in. 

To the right you will see it sorted by faction hub names, and which faction each one belongs to and which region it is in.

Now for an example for the factions. 

http://elgea.illyriad.co.uk/#/Alliance/Faction/80 these are the illians, I am using this faction due to it's diversity of actions/reactions to different races.

When you go to this page you will see it's name at the very top, followed by the race and then region.

Below that is "your standings" which shows you your individual standings with that faction, and your alliances' standings with that faction.  

Below that and to the left hand side is the list of it's "hubs" and to the right shows a short blurb about the faction itself.

On the left and below the hubs, shows known units, which shows which units the faction has available to it.

Further below that is the default racial standings, these show how the faction will interact with each individual race, and how it will affect whole alliances. For example, a pure elven alliance will be +10 faction standings, if you include even one from another race the standings will drop correspondingly. 

Further below shows how the factions will interact with other factions, 

this faction currently has -65 with the lyrians and -70 with the turyns, so if you are friendly with either one of those factions, your standings with this faction will drop as well. Or if you are enemies with those factions, your standings with the illians will rise. 

And finally, here is the table for what each faction standing means

Standing	Meaning
+90	May join on an aggressive missions
+75	May assist city if under siege near territory
+50	May join and assist units if camped in territory
+35	Will offer faction quests
+1 to +35	Will trade at discount prices (sliding scale)
0	Neutral
-1 to -35	Will trade but at inflated prices (sliding scale)
-35	Will refuse to trade
-50	May attack and kill any units they see in "their territory"
-75	Will actively seek out and try to destroy cities within a certain radius of faction hub
-90	Pure hatred, will attempt to destroy at any cost

Here is a guide on faction trading by buttered toast

http://forum.illyriad.co.uk/so-you-wanna-trade-guide-to-basic-faction-trade_topic5382.html