I just noticed this while rewatching the episode. She said this like battle aura is something literal, not some play on words. And later during the fight near the teleportation circle we also see how an attack from Elinalise with a naked blade on Atofe’s neck does not hurt her. So it seems some people in this world are protected from physical attacks by some kind of barrier? That’s not magic, though, because Zanoba sucks at magic. In one of the previous episodes, when the gang teleports to the flying fortress for the first time, I got an impression they were going in an order that corresponds to how much mana they have. I assumed that based on comments about how hard it was to teleport Rudy, who we know has disgusting amount of mana, and that Nanahoshi went first, and we know she has none. So Zanoba doesn’t have much mana either.

@edit
Or it could be magic, since Zanoba is just special (blessed child) 🤔