Today the main epicentre of the remaining insurgency against the Syrian government is the province of Idlib and its environs. Within that milieu are multiple minor jihadi groups that have foreign fighters (muhajireen) in their ranks. Fursan al-Din (Knights of the Religion) is one such group. Fursan al-Din was founded by Turkish muhajireen, but it also has members from central Asia and Europe as well native Syrians. The group has most notably fought in the Latakia and Sahl al-Ghab areas.
Recently I was able to interview the amir of Fursan al-Din, who is himself Turkish, about the history of Fursan al-Din and the current situation. Note this interview was originally conducted in Turkish and the questions and answers have kindly been translated by an anonymous friend. Any explanatory insertions are in square brackets.