Sebu Nefar is from Kohath and was Tofi Dathan’s apprentice. Dathan joined the Kestrel as the Kohathi representative in the search for the alien intruders, and gave his life to help the mission. The Kohathi take apprentices to whom they pass on their skills and learning. The apprentices then carry on the work after them. When the Kestrel needed a doctor after the Intruders mission, Nefar volunteered in order to honour Dathan and continue his work in studying humans and their relationship with the other alien races.
In the early years of study and apprenticeship, Kohathis stay at home and have time to build their marriage relationship and have children. Only later do they begin to travel, initially for short periods, then longer if necessary as they progress. Nefar’s children are grown, so he felt that he was most suited of all the apprentices to go into space away from the family.
The number of apprentices depends on the field of work. Labourers will only have one or two, to whom they will pass on their skills. Particularly in the fields of science, there will be at least three, as it is understood that research often branches into many related fields, and the apprentices can specialise in the separate branches of their mentor’s work. Kohathi do not retire, but as they get older, the apprentices take on more of the work and share their findings with their mentor.
Nefar looks like a genial be-whiskered old man, but all Kohathi males look like that. He is in fact quite young for his race, a mere one hundred and two, and much stronger than he looks, since Kohath is a heavy gravity planet. You don’t argue with Doctor Nefar.