Lu Shu found out that at some point in history, magical energy had grown scarce and the population of the Dragon Clan started to dwindle.
It was probably not because of a massacre. Instead, there might have been a problem with the continuation of the Dragon Clan. Had it become difficult for them to give birth? Lu Shu was not too sure. Another possibility was that the Dragon Clan needed great amounts of magical energy. It was hard for them to survive like they had in the past during the magically scarce era.
Every species had its flaws. Even the powerful Dragon Clan, who were destined to overlook humans, had to rely on magical energy to survive.