5/10 for teaching, 9/10 for character. There are a lot of strange rumours about him, and apparently he tells his life story to each year 12 class at the end of the year. What I have been able to get out of him is that he used to be a photographer for Fifa, and was quite rich until he had a messy divorce (that last part I kind of inferred...)
He doesn't really go by the syllabus, instead going on week-long, untestable tangents. When he notices people are bored, or perhaps sleepy, he starts shouting, though not angrily. He just shouts.