Well, I do not think there is a "devil". The only "Satan" is the baser nature of every person's Self. I have a "satan" within me, it is my unGodly nature. I also have God within me, it is my Godly nature. When I seek to act for myself alone, I am following "satan", when I seek to act for others I am following God.
Every man or woman who has ever lived and those yet to be born are "servants of God". We can perform that service well or poorly, but we can never counter the will of God with our own in the long run.
"Cause us, then, to be so steadfast in our love towards Thee that we will turn to none except Thee, and will be reckoned amongst them that are brought nigh to Thee, and acknowledge Thee as One Who is exalted above every comparison and is holy beyond all likeness, and will lift up our voices amongst Thy servants and cry aloud that He is the one God, the Incomparable, the Ever-Abiding, the Most Powerful, the All-Glorious, the All-Wise."
(Baha'u'llah, Prayers and Meditations by Baha'u'llah, p. 38)
"All belong to the Adamic tree, -- all are sheltered beneath the protecting mercy and providence of God. All are the children of God; all are fruit upon the one tree of His love. God is clement and kind to all the branches, leaves and fruit of this tree and there is no existence or interference of a satanic tree whatever, -- Satan being a creation of human proclivities. God alone is the Creator and all are creatures of His might. Therefore we must love all mankind as His creatures and realize that all are growing upon the Tree of His mercy -- that all are servants of His almighty Will and manifestations of His good pleasure."
(Compilations, Baha'i Scriptures, p. 347)