Several from my country (Denmark) has traveled to Syria and joined the IS-forces. They have danish citizenship and danish passports, but they are really immigrants from the MiddleEast or 1. or 2. generation descendants of immigrants. They have no real connection to the danish society, most live on welfare, and this is an "exciting" way for them to confirm their identity as muslims and not-danish. There has been reports in danish newsmedia that some of these people have been killed - some from their "own" side when they found out war is a scary and dangerous business, and they wanted to leave.