There are currently 6 main factions with which you can gain/lose reputation. These factions can be accessed by using the local map. When your guinea pig messengers are ready you can select a faction and choose certain options for certain benefits. Each faction is listed below with their specific options, conditions and consequences. Since Vengeful Archimage patch having high(+25,+75) or low(-25,-75) reputation gives you passive bonuses or maluses respectively.
Map Specific Factions
Each map have its own quest related to them, getting harder as the campaing goes on. Most of these reward you a star for raising their affection level to 90, with diferent prerequisites.