Syria's civil war started in 2011, when a number of young graffiti artists spray-painted a few anti-regime slogans across the walls in Syria's southern city of Deraa. They were seized by local government forces, held, tortured and in some cases murdered. http://www.aljazeera.com/news/2016/05/syria-civil-war-explained-160505084119966.html The local population rose up in outrage and demanded the release of the remaining teens. The Syrian uprising soon spread to other cities across Syria as popular outrage swept throughout Syria's long dormant Sunni-majority against the minority Alawite-Shia dominated government. The government had long been dominated by the Al-Assads, first Hafez, and upon Hafez's death, by his son, Bashar. Bashar Al-Assad and his regime responded to the mass-protests bubbling up in his country with mass-violence, allegedly shooting many protesters.
The protests soon morphed into armed resistance. There were defections from the Syrian Arab Army (as the Syrian governmental military calls itself) to what was quickly forming up to become the Free Syrian Army. http://www.understandingwar.org/report/free-syrian-army.
The Free Syrian Army has hosted many defectors from Bashar Al-Assad's ranks, yet remained a fractitious group, with hundreds, if not thousands, of disparate brigades under a plethora of differing command structures. The Free Syrian Army has also seen many defections in recent years to more militantly-islamist rebel factions fighting against Assad's forces.
Assad's forces have been bolstered by Iranian Republican Guards and the Lebanese Shia military organization called Hezbollah, who invaded western Syria to stabilize Lebanon's eastern border it shares with Syria. Hezbollah has been instrumental in Assad's forces securing this border area against islamist rebels. http://www.newyorker.com/magazine/2013/02/25/after-syria
Perhaps the most destructive force confronting Syria is the black flag of the Islamic State, which swept into eastern Syria from Iraq in 2013/14, conquering the Syrian city Al Raqqua as the capitol of its self-proclaimed "Caliphate". The hyper-islamist group, has fought it out with its fellow rebels as much as it has Bashar Al-Assad's regime forces. As it took one rebel/government stronghold after another, this forward progression culminated in its high-water mark, when Isis re-invaded Iraq from Syrian soil, taking Mosul, Iraq's second biggest city.
Top: Iraqi troops leaving Mosul. Bottom: Isis member gleefully entering the city.
The battle for re-taking Mosul was undertaken by a coalition of Iraqi forces last October, and it yet has to be fully conquered, with the eastern portion of the city hard-won, with the west as of yet to be had. With the eventual defeat of Isis in Mosul, a number of forces, including the Kurds, are looking across Iraq's border back into Syria, at the much-anticipated battle against Isis's de facto capital, Al Raqqa.
This brings us to perhaps the most gleaming prospect of the whole Syrian episode, the re-emergence of the Kurds. The Kurds are the regions most progressive entity, with even all-female fighting units, called the YPG, fighting Isis tooth and nail. If any bright side can be said to be had, it would be the Kurds coming out on top in northern Syria, despite Turkish misgivings. Out of all of the bad actors in the region, Bashar Al-Assad's SAA, the various Jihadist groups, the Russians and even the Turks, the Kurds and the kurds alone hold a place of untarnished validity.
A member of the Kurdish YPG