Arika Yumemiya has come to Windbloom Kingdom in search of her mother, whom Arika knows was an Otome. On her arrival she meets the top Coral Otome student, Nina Wáng, and Windbloom's heir to the throne, Mashiro Blan de Windbloom. The series follows Arika's progress as a student at Garderobe Academy and the machinations of those desiring the destructive power of the old technology for themselves.
(taken from Wiki.)

Picture	Real Name	Description
	Arika Yumemiya	A main character of My-Otome. She enters Garderobe dreaming of becoming an Otome like her mother. She possesses the Blue Sky Sapphire (Souten no Seigyoku?), a memento from her mother.
	Nina Wáng	A main character of My-Otome. As the top Coral student, Nina dreams to become a great Otome to make Sergay, her adoptive father, proud. She dislikes Arika from the moment they meet. Later in the series she receives the Ultimate Black Diamond (Shikkoku no Kongouseki?).
	Nao Yuuki	Nao is a morally ambivalent red haired young woman with something of a cruel streak; in particular she enjoys tormenting Natsuki. She is also frequently associated with spiders and uses razor-sharp wires as her weapon of choice.
	Erstin Ho	Arika's and Nina's roommate, from the country of Annan. Erstin mostly serves as a bridge between Arika and Nina, who don't get along very well.
	Irina Woods	Irina is one of Arika's friends from the Aries Republic. She shows a love for technology and is under the tutelage of Yohko.
	Tomoe Marguerite	She is Coral No. 2 and a room attendant for Chie. On the outside she acts normal but is jealous of Arika's and Shizuru's relationship.
	Akane Soir	The top Pearl student and leader of the Trias. She becomes torn between her love for Kazuya and her dreams of becoming a Meister Otome. The GEM she receives upon appointment as Meister is the Pure Heart Malachite (Seiren no Kujakuishi?).