What problem did the converts have with the osu joining the church?

Controversy rises in the young church over the question of admitting the osu, a caste of outcasts who are set aside in dedication to the gods. They are not allowed to use razors, and their dead are buried in the evil forest. Mr. Kiaga demands that the outcasts be accepted. The osu shave their heads, at Mr. Kiaga's encouragement, and they soon become the most faithful followers of the new faith. More trouble arises when one of these osu converts kills a python, which is a sacred animal and the emanation of the god of water.