Demos is indeed stronger than the current Cassandra... much stronger!
From Lann's understanding of this Ancient Greek world, their strength mainly depends on the connection with the prehistoric First Civilization, that is, the Elder Race.
Those with Elder Race bloodlines are stronger than ordinary people. And if the Elder Race bloodline can be paired with the use of Elder Race Divine Artifacts, they are even stronger.
But Cassandra and Demos, the uniqueness of these two siblings in this world is that—not only do they have an astonishingly high purity of bloodline, but the weapons in their hands are also frightening!
In this Ancient Greek world, in ordinary contexts, 'Divine Artifact' refers to pieces of Elder Race Divine Artifacts that humans dig out from underground, which are remains of the Elder Race's technological materials, then reforged by human craftsmen.
