Noa Ehn

Former princesss of Estabul, the only daughter of King of Estabul, Ruwe Ehn (ルウェ・エン?), Noa is a seventeen year old (when first introduced) beauty with navy-blue long hair tied up in a ponytail. She has a very sharp and brilliant mind, and is well-loved by the people of Estabul.
While technically, Noa was the figurehead of the rebellion against Estabul's liege country, Roland, she was actually used by Salawel (サラウェル Saraweru?), a noble of Estabul whom she trusts. After the rebellion was suppressed by Claugh Klom and Miran Froaude, she was nearly killed by Froaude if not for Claugh's intervention. Thereafter, she was inducted into the nobility of Roland as part of a peaceful effort to stabilize Estabul, and subsequently resides within the royal compounds of Roland. She is in a love relationship with Claugh, who is six years older, and constantly worries about his well-being as he has a tendency to overdo things.

(Source: Wikipedia)