Ben Kyoshi
べン先生
                    
                    
                                A perverted, insane, abusive, sadistic, mad scientist teacher who works for Toenail of Satan. He always punishes Mayumi Takahashi for failing on her grades and always gets defeated by Kekko Kamen.
(Source: Wikipedia)
                        (Source: Wikipedia)
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                                                        Kekkou Kamen
Supporting (Role) OVA