Noin is one of higher demons in Jeanne. He and his [well that pink-haired girl] appear on the beginning of second season of Jeanne. They both have to elliminate Jeanne, however don't fight just for themselves, but use demons [which are stronger too].
       Noin's alter-ego is a high-pasion history teacher from France. He has red hair [originally gray]. He know Jeanne's true personality, means Maron, though she doesn't know he is Noin. He hands her a letter from her father [yeah likely], telling he knew him and all the time he's just being nice to her. Plus he appears everywhere demons are... but well he seems to like her after all... yeah happens sometimes...
       Well he's a demon, but a kind of _not_too_bad_one_, I guess I like that girly pink-haired girly better... yeah well...