Shimada

He is Sakaguchi's middle school teacher and the only one who is patient enough to still find hope in him despite of his constant trouble making and rowdy behavior in his class. Though he is aware that Sakaguchi only attends his class because of his admiration to Reiko Minami, the school's pretties teacher, he still tries his best to put him on the right path, but, to no avail, since the latter is just too stubborn to be reasoned with in the first place.

(Source: ANN)