Are you from a time period with chainsaws? It's like that, but balanced and designed to act as a sword. [He has to assume they had chainsaws on ancient Terra! How else would they do their logging/beheading?]
Anyway, we volunteer. Spreading the teachings of the sword to others strikes me as a vaguely noble endeavor, while at once it keeps my students from otherwise being extremely bored three times a week. [He grins.]