Assad's nightmare: Meet Tahrir al-Sham leader, Abu Mohammad al-Julani

North western Syria is now entirely out of President Assad's control, mostly to the efforts of a Sunni coalition known as Hay'at Tahrir al-Sham, a Salafist Jihadi organization headed by Abu Mohammad al-Julani, an elusive figure who broke contact with both ISIS and Al Qaeda to take his group in a new direction