Oni no Ou to Chigire - Chapter 2 Pg 50

Once it was just the two of them, Yato let out a short whistle.

Scary! As usual, that guy is cold to anyone in the clan whos not a demon master.

Thats because demon masters are Katsumoto-sans top priority.

I dont really like that guy.

Well, hes not someone you want to let your guard down around.

Tokimori spoke honestly. He could see demons, he was knowledgeable and prudent, and Tokimori could rely on him more than his own family, but that was it. Tokimori didnt personally value Katsumoto, first because he was from the main household, and second because he had a feeling that as a demon master, he would be stuck with him for a long time. He respected Tokimori as his master, even though their age difference was like father and son, because he was a demon master, and would do anything to protect him. However, he was the sort of man that would immediately report to the main household if Tokimori or Yato broke any rules, or did something that wouldnt benefit the main household, and handle their punishment. The way he was able to obiently act on the orders from the main household without letting his emotions get in the way, he would have made a fine demon master, but he was not born as such.

It is determined whether a child from a demon master blood line would be born with the abilities of a demon master while they were still a fetus residing in their mothers womb.