User blog comment:Gundam Legilis/Volume 1 Weapons In Depth - Melodic Cudgel/@comment-3146930-20140721020908/@comment-96.236.69.172-20140721033923

Their aura helps them take hits. Like how in the yellow trailer, the bad guys didn't exactly have exit wounds after being shot by Yang and Ember Celica. I assume it still hurts and, if done enough, could possibly wear out their aura and "take more damage".