Oni no Ou to Chigire - Chapter 3 Pg 71

Come to think of it, Yato didnt talk much whenever they were around other demon masters, and would get stiff like a doll while holding on tightly to Tokimori. Even if Tokimori was made fun of, Yato wouldnt complain on the spot, but once they got home and it was just the two of them, hed let out all his curses. Yato must have been the type that was arrogant at home, but shy out in public. Thinking that was cute, Tokimori rubbed his cheek against Yatos head.

Dont worry about him, Tokimori. That old man is getting senile, seems like he doesnt get many jobs anymore. He lost his ability to come up with plans for his jobs. Now he only lives for attending these Summer Solstice Gatherings. I heard theyre going to tell him to retire soon.

Retire?

There wasnt a retirement age for demon masters, but if they were unable to work, they had no choice but to retire. He would inform his employed demon that the contract was void, and would return the blood given to him during the contract exchange. The way they would return their blood was by the demon biting their masters neck like a vampire, and sucking it back out. Afterwards, their relationship as a demon master and demon servant will return to a clean slate. Even though demon masters had their abilities until they died, once they retired, they would never form another contract with a demon again. Tokimori didnt think too hard about how many decades it would be until he retired. Yato had been by his side even before they formed an official contract, and he had promised to stay with him forever, even after he retired from being a demon master. If he had said he was actually looking forward to retirement so he could be released from his work, that old man probably would have gotten so angry hed burst into flames.