Izetta: The Last Witch
Episode 5
S1 E5:
Izetta is powerful enough to fight whole armies, but her strength is limited. She can only use her abilities near certain ley lines, and outside them, she's no different than a normal girl. When the Germanian army attacks in a spot far from these ley lines, the duchy is forced into a corner: how can they repel these foes without giving up the secret of Izetta's strength?