Rightful Rightful/Christian Christian Tyrant/Christian Tyrant Tyrant/Old Faith Old Faith Rightful/Old Faith
As you play, you come to face different quests, battles, talks and diplomacy. Your decisions during these events affect how the people look at you. Your public image is visualized on a plane, where in the horizontal axis you can see the attitude of worshippers of two main religions in Britannia - Christianity and the Old Faith - think of you, whereas on the vertical axis you see the history of how you treated your serves and solved kingdom-management problems - you can either be the rightful king, or prefer tyranny as the right way to progress. The relationship is reciprocal: your gameplay affects your image, but your image will also greatly impact your gameplay.
Basically, there are quite a few spells that are granted to you taking into concern your attitude to religion - being Old Faith supporter, you come to have a handful of natural disasters spells, whereas supporting Christianity enables you to use spells provided by the allmighty - Sanctuary, Wrath of God...
Being rightful ruler enables you to take kingdom-management-friendly actions, whereas a tyrant-friendly leader has an access to dirty wargame practices.
Special units accessible are also the outcome of your alignment. Being Old Faith supporter enables you to make friends with the elder race of Seelie and/or Unseelie, while Christianity lets you call to service various zealots and armed defenders of faith. Rightfulness grants glamorous shiny noble knights to your side, and Tyranny calls for using raiders, marauders and other brawlers.
Your knights are usually a colourful bunch and also have their alignment. Some of your companions will not so easily accept your way of thinking!