It is important to note that while on the outset the conflict seems to be about religion sectarianism (Sunni vs. Shi'a), it is in reality about social groups and power and not a schism with respect to religious content.
We follow current proposals not to call the group ISIS as this implies the existence of a state. Given our discussion it should be clear that we do not think of DAESH as a state.
Pipes, D. (2013), “Explaining the Denial: Denying Islam's Role in Terror,” Middle East Quarterly , 20, 3–12.
For example, Abu Bakr al-Baghdadi the leader of DAESH spent almost five years imprisoned at Camp Bucca in southern Iraq, side by side with other extremists such as Abu Muslim al-Turkmani, Abu Louay, Abu Kassem, Abu Jurnas, Abu Shema and Abu Suja. These extremists were held side-by-side with those less radical, allowing U.S.-coalition prisons in Iraq to essentially become recruitment centers and even training grounds for ISIS recruits.