Billy and Adrien listened to Erend's words with anxious and worried hearts.
For them, Erend was the one who knew the most about Magic matters. And on top of that, he had a good relationship with an Elf Princess.
That way he has access to far more information than they do.
When Erend said that there would be a great disaster coming in a year, they all believed in it.
And when Erend advised them to start learning Magic so they could defend themselves and their families, Billy and Adrien felt that it would be good if they followed Erend's words. Even if they don't really agree.
When they saw that there was an experiment the government was carrying out in secret so they could create humans to use Magic, it was very surprising.
But Adrien had suspected it for a long time.