Writing for The National Interest, Ted Galen Carpenter discusses the emergence of a Kurdish autonomous region in northeastern Syria. If added to the Kurdish autonomous region now extant in northern Iraq, the combined area could become the nucleus of a Greater Kurdistan that might eventually encompass the Kurd-majority parts of Turkey, Iraq, Syria, and Iran.
Kurds are not Turks, nor Arabs, nor Persians. Although Turks deny it, anthropologists agree Kurds are a distinct ethnic group. Carpenter calls them "the largest ethnic group in the world without a homeland." See his map for Kurdish-populated regions.
For reasons that are unclear, Kurds seem better able to govern themselves effectively than either Arabs or Persians. That has been the case in post-Saddam Iraq and is becoming the case in northeast Syria as well. An eventual Greater Kurdistan would be a serious player in this volatile region.
While Kurds are mostly Sunni Muslims, there are also significant numbers of Shia Muslims, as well as two syncretic religions: Ahl-i Haqq and Yazidis. Wikipedia calls Kurds "the most religiously diverse people of West Asia."
