As an ESWAT member, Deunan is a specialist in weapons handling, explosive devices manipulations, hand-to-hand combat, and an excellent Landmate pilot. According the Appleseed Databook, she is trained to be ambidextrous. In the original manga, Briareos was a cyborg before Deunan arrived at Olympus, and she managed to lose an eye in Volume 4, due to a training accident.
The following data is from the 2004 Movie adaptation.
The daughter of Carl and Dr. Gilliam Knute, Deunan, who is considered as a highly skilled warrior, has spent almost her entire life fighting in a war that was, for the most part, over. It wasn't until she was captured by an ES.W.A.T. (Especial Weapons And Tactics) team in the middle of a ruined city, led by Hitomi and her former lover Briareos, that she was finally evacuated from the Badlands. When she arrived in Olympus, the change of environment was severe, but it was a greater shock to her when she found that Briareos had lost over 75% of his original body during the last Global War and was now a cyborg.
The day after she was brought to the city of Olympus, Deunan learned that over half of the population of the city was composed of artificial humans called Bioroids. She also found out that her new friend, Hitomi, was one herself. Deunan also discovers that other people are looking for her, mostly because she possesses, without knowing it, the secret of "Appleseed". That interest will become important when Hitomi's life will be at risk and that the "Appleseed Data" will be needed to save her. But that would mean defying the powerful Olympus Regular Army (ORA), composed at 100% of humans and under the command of General Uranus and Colonel Hades.
- Wikipedia