Leliana was previously confirmed to make an appearance in Inquisition, and according to the character's page on the official Dragon Age site, her "devotion to the Maker is matched only by her devotion to Divine Justinia V, a woman who is both mentor and savior."
Several screens show Leliana's new appearance and hint at her role as "the shadow behind the Sunburst Throne" in Inquisition.
The character's first appearance was in Dragon Age: Origins as a recruitable party member. She went on to appear briefly in the game's sequel, Dragon Age II.
Just a few days ago BioWare revealed Dorian as a party member, described by writer David Gaider as "legitimately gay."