Dori and Gura
are twin archers serving under Oboro. There are several ways to tell them apart: Dori has purple eyes while Gura's are blue, and the bottom part of Dori's clothes is blue while with Gura they are red. Their gender is difficult to ascertain, even by other characters. Dori and Gura get their lord Oboro drunk, resulting in Oboro waking up with the twins in his arms and finding that all three of them are naked. Spoiler!In the conclusion of anime, they stay with Oboro as he travels the world.
Akeno Watanabe (Japanese), Brittney Karbowski, (Dori) & Nancy Novotny (Gura) (English)