He's the camera boy of Humanity Has Declined anime series.
Sweet Girl's Assistant has no name as of now, and he is originally created by Romeo Tanaka and designed by Sunaho Tobe and Toru Yamasaki. He first appears in Humanity Has Declined episode 1.
He is seen handing food to Sweet Girl, and he accompanies the village leader and Sweet Girl to a factory. He is the camera man who is mute.