All settings can be edited from Project Settings -> Game -> Factions tab.
Factions settings are defined by right and left areas.
At the left you have a list of all factions, with a little search box in case you have more than you can deal with.
At the right you will find all the properties of a selected faction (which was selected by just clicking on it on the list).
You can also rename factions by double clicking on them.
All Faction information can be read on runtime too:
Relations define how will two factions interact to each other.
In this example, Brotherhood and Triggermen are enemies:
By default there are three possible attitudes: Hostile, Neutral and Friendly