ISIS media wing Wilayat al-Furat has released a video revolving vastly around the training of child soldiers. The kids are also made to attend an execution of a man hanged upside down by having his throat slashed. Later in the video, a child soldier executes a captured man by shooting him at point blank range in the top of the head.
The original video is over 28 minutes long. Most of it is the Islamic propaganda and the indoctrination of child soldiers. The beheading of the upside down man starts at around 14:50. The gunshot execution at around 18:28.
I’m not sure where exactly the video is from, but could be Ar-Raqqa in Syria. Props to Best Gore member @13lunt420media for the video: