Satan is depicted as a treacherous master manipulator with a talent for words, he is said to rely heavily on his reputation but has his pawns do all the dirty work - when confronted Satan will try to turn the tables on his opponents and gain possession of a would-be-victim via trickery or falsehoods, yet when his true nature is revealed he quickly leaves as he can not stand to be among those of strong faith.
Satan manifested as an authority figure in a small community and used his influence to form a white supremicist group that twisted faith into aggression - this angered Tess to the point she temporary lost her angelic powers and was replaced by another angel named Sam. However after reconciling with God, Tess joined the other angels in a raid of the area Satan was corrupting, where they revealed his true nature to his would-be-pawns and ultimately foiled his plan.
Satan is depicted as being a powerful supernatural being who can appear as almost anything he desires - however when dealing with humans he is limited to utilizing their own free-will against them, exploiting pre-existing hate, fear or anger in order to manipulate them into breaking away from God and the postive side of life .
Satan seems to view freewill as a curse, as he noted to Tess once, trying to control others and stealing their gifts and ultimately their lives - subtly leading them on the path of ruin.