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“I really need to start upping my expectations for what you’re actually capable of,” she said wryly. “Anyway. I’m guessing there’s more defenses than just that barrier up there protecting us from being crushed under the weight of the ocean?”

“Loads,” I said without specifying.

The main defense of the castle was in its ability to be submerged and hidden from sight, true, but the characteristic attribute of it was actually in its flexibility. Unlike most of the other castles I’d come across in my comparisons, Castle Avalon’s fortifications weren’t too far beyond ordinary — nothing like Lancelot’s Joyeuse Garde, which stripped intruders of their identities and forced them to fight a gauntlet of knights to regain the memory of their names — but it made up for it by making any fortification added part of the Noble Phantasm.

That was mostly a side effect, though, of how it had been constructed and its true ability, the thing that made it Nimue’s Noble Phantasm rather than just a generic castle.