Angels
Angels (also referred to as Celestials) are otherworldly beings that occasionally appear on Earth. The mirror image of demons, Angels embody a specific 'virtue' (where demons embody a specific 'sin' or 'vice), very frequently putting them at odds with demons, and often humanity itself. In embodying a virtue, an Angel must strive to uphold that virtue whenever possible, in both themselves and others.
Even more than demons, Angelic society exists on strata and class, with Archangels being the most powerful, Seraphim in the middle, and Lower Angels being the weakest, and every caste having it's own unique dialect within the Angelic language.
While most angels are indifferent towards mortals, some have known to become interested in their affairs and often reveal themselves to those who prove worthy, or even just entertaining. Rarely angels will work with humans outright to further some sort of goal. The most commonly known of these is the Archangel Justice.