The mention of survivors from the war a thousand years ago made everyone gasp in surprise, but before they could fully process it, a powerful aura appeared in the room. The three elders, Daphne, Diana, Ariza, Kenia, and even Oliver were shocked to see an old, wrinkled woman, who, despite her age, still showed signs of having been very beautiful in her youth.
Andrew doesn't react because he already knows about the old woman's existence. Since the first time he came to this castle, he had sensed her—well, Fluffy did—but since she had never appeared or attempted to contact him, he paid her no mind.
Even now, she didn't seem interested in showing herself directly to him, which is why he had ignored her. However, seeing her now, he understood that it wasn't that she hadn't paid attention to him, but rather that she had been doing so subtly.