Jeanne d'Arc 30th (also known as Durandal or Diamond Dust Witch) is an ice ability user from EU (a criminal organization). During the events in Volume 2 of the light novel, she targets Shirayuki in an attempt to kidnap her and force her to join EU. She is successfully captured via the combined efforts of Aria, Kinji and Shirayuki during the season of Adseard. As one of the conditions of her plea bargain, she was forced to stay in Butei High as a 2nd year international student from Paris enrolled in the Informa department. As a reliable Informa student, Kinji requests her aid whenever he needs a supply of knowledge about a particular case he is involved at. Jeanne and Riko get along with each other very well.
She is one of the few people that knows Kinji's secret. Her personality is serious and cool. Her first comment about Butei High's skirt is: "Unmarried girls shouldn't openly reveal their legs like this!". However, that notion was pretty much shattered because of Riko's strong influence on her, and she has grown a habit of secretly collecting maid dresses, Lolita fashion and other cute dresses.
Although Jeanne is quite extraordinary in terms of fighting skills, beauty and ability, her drawing skills are unimpressive. Despite her strength, she alleges that she is the weakest out of all the members of EU.
(Source: Hidan no Aria Wiki)