Heavy Artillery

Every person below me in the entire length of the battlefield on my side of the wall suddenly collapsed to the ground. Some used magic to blow themselves up, some just used a knife or sword to slice their own throats, and the monsters seemed to have all snapped their own necks. "More effective than I thought it would be. I was scared that if used in such a wide area that my own people would end up killing themselves but now that it is tested and foolproof,  only I need to go out to the battlefield in the future. That Earth Wall made a for a good soundproofing material."