Mephisto Pheles is the Chairman of True Cross Academy and also an Exorcist. After Fujimoto's death Pheles was ordered to kill Rin, however he accepted Rin's proposal in becoming an Exorcist and entered him into True Cross Academy. It has been heavily implied that he is the son of Satan along with his brother, the Earth King, Amaimon. He possesses the unique and peculiar ability of transforming into a small dog after counting to three in German. How powerful he is has not been shown but he has mentioned that he is an Honorary Knight, the position two ranks below Paladin. He has been shown responsible for allowing several higher class demons onto campus. His name is an obvious pun on the word Mephistopheles, which is name for the another infamous devil, similar to his father Satan. (Sources: VIZ Media)

Tsugumi is a hitwoman who was raised and trained by Claude of the Beehive Gangsters.Tsugumi is originally introduced as a guy who transfers to Chitoge's class, and has orders to protect her from Raku, whom she thinks forced Chitoge into the relationship. She and Chitoge are childhood friends; she tries to keep a ten year old promise of becoming strong to protect Chitoge. However, after Raku treats her nicely, she begins to develop some feelings for him, even though she is too stubborn and embarrassed to admit it. In America, her assassin code name is "Black Tiger," who had a rivalry with "White Fang." She does well academically, having ranked next to Chitoge on a yearly exam. (Source: Wikipedia)