Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 4
Yes, certainly [there are hostile forces active in the outside world]. Men are being constantly invaded by the hostiles and 
there are great numbers of men who are partly or entirely under their influence. Some are possessed by them, others (a few) are incarnations of hostile beings. At the present moment they are very active all over the earth. Of course in the outside world there is no consciousness such as is developed in Yoga, by which they can either become aware of or consciously repel the attacks – the struggle in them between the psychic and the hostile force goes on mostly behind the veil or so far as it is on the surface is not understood by the mind.