Rex was not totally ignorant about the Scions from the Sadness Stratum.
He had met with one, Kei Xun.
But he truly understood now that she was already defeated, a fallen Scion who no longer fought to reach the Highseat of Invincibility. Her drive remained sadness; it was shown through her attempt to dissuade Rex from continuing to walk the path of a Scion.
Unfortunately, her drive had already been weakened.
She no longer sought to get stronger.
No reasoning in her sadness that fixed her mind on getting stronger.
Diamantona, on the other hand, was the complete opposite.
He embodies the Sadness Stratum like an old glove.
Similar to Kei Xun—he has a pessimistic view of the future. Being blessed with the capability to see the past made him see only darkness. The future is the natural consequence of the past, and all he saw was darkness.
But unlike Kei Xun, he channelled that pessimistic view into something else.
A sharpening tool for his mind to push him to grow stronger.
