Celestia glossed over the general ideas, he clearly didn’t quite understand what she meant while explaining their dietary habits. The changeling was an infiltrator, a spy, a saboteur, and assassin. He was an operative of Queen Chrysalis, an all but defunct Changeling monarch in the badlands. A remnant of a failed invasion. However his refusal to fight during the attack branded him a coward. He was an outcast from his hive, dishonored and never to return.