As Syria's war enters its fifth year, VICE News filmmaker Medyan Dairieh traveled to the shattered northern city of Aleppo, where fighters from the US-backed moderate rebel group Jaish al-Mujahideen are still holding out against government forces in the city's western half and Islamic State (ISIS) fighters in the eastern countryside.For these rebels and their families, local fighters from the northern countryside, Aleppo's abandoned ruins have become home. More than 13,000 Syrian children have been killed in the war so far — for those who survive, a childhood lived under bombardment and the sound of gunfire casts a dark shadow across their future. From a young age they are trained how to handle weapons, with their parents aiming for them to become the next generation of rebel fighters.