Imperial Aegis

After Evelyn took over Peldra, she created the Imperial Aegis. This massive, country-wide spell protects whoever possess it and is capable of stopping almost anything short of an orbital bombardment.

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When she abdicated, Evelyn set the Imperial Aegis to go to whoever killed her. This ended up being Vania.

Later on, when rebels attacked, they shattered the keystone of the Imperial Aegis.