All along, Esme's mother, Anastasia was just an ordinary person, neither royalty nor god hence she did not possess an ounce of magic. But what she lacked in this aspect was made up by her with her intelligence and courage.
The late King of Nevesray saw that and took in the young and orphan Anastasia and made her indebted to him by doing that. He trained her in politics and combat.
Anastasia was a loyal person and she did not turn her back on the person who picked her up from the streets and provided with a better life.
Without an ounce of magic in her body and just with the illusion of possessing the magic, she became the most powerful queen who unified Nevesray which was initially divided in different territories. Not only she terrified the other monarchs, but even the ordinary people of the Kingdom sang tales of her glory.