I am an Eastern Orthodox Christian who has been studying theology and by default, demonology for over 8 years. To be a theologian, is to be one who prays. So says St. Maximos the Confessor and so says the multitude of saints, holy elders and monastics who have come before or since.
Every believer is called to strive against the devil and his demons. In that sense, every believer is an exorcist. But there is only ONE true Exorcist: Our Lord Jesus Christ, the son of God. May he have mercy on me, a sinner.
I am in the process of preparing an FAQ from the Eastern Orthodox Christian perspective about demons, angels and the study of theology. I will try to reference all sources available in English, but it will be quite difficult to find as most are still as yet untranslated and in eastern languages. There is much to be learned from the Roman Catholic Church and it's libraries. But I would be dishonest if I said I felt that to be complete. The study of demonology and of angels in general, will never be complete unless it's Eastern Orthodox perspective is given.
Most holy Theotokos, Defender of Humankind, pray for us, as we tread the earth in search of God and salvation.