The mentors in the Killing Techniques Palace had rotational duties since, as Conferred Knights, they had too many tasks, and they could only take turns to do things like providing guidance on sword arts.
Usually, other than the four and a half hours in the morning and four and a half hours in the afternoon, there were no mentors on duty for the rest of the day.
Oftentimes the person on duty was not a teacher, and was instead a student.
However, the sword arts mastery of these students was not to be underestimated either. They had all reached the maximum level in the sword technique that they were mentoring. They could even have started practicing the sword techniques from the later stages of the Killing Techniques Palace and had either completed or were trying to complete the skills synthesis.
Of course, even after they have completed the synthesis, they would still know the essence to the Thunderbolt Sword Technique and could still perform it.
