A 16-year-old bracer in training, and protagonist of the series. Has a bubbly personality with a never-give-up spirit and a general tendency toward bee-lining straight for whatever her heart may desire. Also somewhat naive, and the perfect example of a tomboy. Five years ago her father, Cassius, brought home a young boy named Joshua who quickly became like a brother to her. Well trained in martial arts by her father, she wields a bo-style staff with incredible ease—despite the fact that its length is greater than her own height. Estelle has no restrictions on element affiliation and therefore is able to use a variety of orbal arts. Her father Cassius is also an "S" ranked bracer—one of only four in the entire world, and Estelle knows very little of his past.

(Source: Sora no Kiseki/Trails in the Sky First Chapter instruction manual)