Angels are mentioned by Dark Oak during the Blood And Smoke quest, by Hai Len during the Hopeless Romantic quest and by Claude in one of his battle quotes. They are also referred to in the names of the paragon skills Angelic Bond and Angelic Protection. All Chants also include glowing, transparent wings as part of their skill animation.
No known angels have been encountered in any of the existing Guild Wars campaigns, although the appearance of the Avatars of Dwayna is consistent with many western depictions of angels. The Nightfall manual mentions that there are legends that the Harpies are the corrupted descendants of beautiful winged creatures who served Dwayna, which also may have been angels.