Read and you'll see...

While Sybel was simply able to understand and be understood by Them, each of her gifted descendants were more powerful and breathtaking than the last. It was always the youngest child who was granted the gift, and it was Selene who learnt the most valuable lesson of all - with unique power comes great amounts of regret. Ultimately, it was up to her to decide whether the happiness or the safety of the people was more important.