"But we can't just leave," Sophie said firmly.
Josh nodded. "We're not going anywhere."
[… Flamel] glanced at Sophie and Josh. "You have no choice. If you want to survive the rest of the day, you have to leave now." (5.1-3)
Ah, Nicholas, you of all people know that when we are gone, when the Elder Race is no more, when even the humani have gone from this earth, then the Allta clans will reclaim it for themselves. Remember, this world belonged to the Were clans first. (14.6)
In recent years, Nicholas would sometimes awaken at the quietest hour of night with a single thought spinning round and round in his head: if he had known then what he knew now about the Codex, would he have continued his research into the philosopher's stone? […] Most nights he answered yes: even knowing all he knew now, he would still have continued his studies and become the Alchemyst. But there were rare occasions, like today, when the answer was no [… there was] a chance that he had doomed the world. (18.20)