Ibadis were the first group of muslims to break off from the main faith, declaring all other muslims to be non-believers. In game the Ibadis are apparently a Sunni heresy. I think this is wrong and that Ibadi should be considered a branch of Islam the same way Miaphysites are now a branch of Christianity.
http://en.wikipedia.org/wiki/Rustamids
http://en.wikipedia.org/wiki/Ibādiyya
http://en.wikipedia.org/wiki/Rustamids
http://en.wikipedia.org/wiki/Ibādiyya