Rising of the Shield Hero

Naofumi and his friends are fighting in the Dark Coliseum in order to rescue the demi-human Lurolona villagers. The mysterious woman who they encountered there, Nadia, seems to be aware of their objective-and warns them that it's better to give up on it. As they proceed to face off against Nadia in a showdown in the ring, Raphtalia seems to be acting strange-but what could it mean?