Oni no Ou to Chigire - Chapter 2 Pg 41

However, continuous mixing with humans weakened the demon blood which resulted in normal humans being born who could not see demons. The Yase clan was headed toward crisis, so they intermarried over and over again, but was still unsuccessful. Generations passed, but by the end of World War II the number of demon masters decreased dramatically. He had been told that back in their prime there were over three hundred demon masters, but currently there were only sixty-five. Meaning, Tokimori who had been born in the Heisei era, was an endangered species.

if demon masters continue to not be born, I wonder what will happen to the Yase family.

Tokimori muttered as he pressed his chin on top of Yatos head.

Theyll probably fall apart, right?

Yato easily replied since he had no emotional attachments to the Yase family. There was no retirement age for a demon master, but they cant beat old age. The eldest demon master was certainly eighty-three years old, but there were ten of them in their seventies. Even if a demon master baby was born now, they wouldnt be able to work until they were fifteen. Unless some miracle occurred, the number of demon masters would continue to decrease from here on out. The Yase family that flourished because of their demon masters would cease to exist if they lost them.