We aren't actually told that much about this character in this excellent short story. She only appears for two paragraphs, but in those two paragraphs she definitely manages to make an impression and leave her mark! Consider what we are told about her:
It was then that Diana Moon Glampers, the Handicapper General, came into the studio with a double-barreled ten-gauge shotgun. She fired twice, and the Emperor and the Empress were dead before they hit the floor.
Diana Moon Glampers loaded the gun again. She aimed it at the musicians and told them they had ten seconds to get their handicaps back on.
It is at this stage that the television screen goes blank, so no more is seen by the Bergerons. However, we can see from Diana Moon Glamper's brief role that she is definitely a force to be reckoned with. She is ruthless and violent in the way that she shoots Harrison Bergeron and his Empress, she is also threatening in her attitude towards the musicians and clearly feels she has power.