[Necedofer]

There is no power recognized by Hinduism as devil power. It is a power. That is all. Yakshis, Pishchinis etc. are semi divine powers. With the help of mantras one can please them and get them to do what they want. But it has its own drawbacks also as most Mantrics know. Yakshis do protect people also and in some places are worshipped. Some of these powers also help in curing people.

Karnapiasachini is one power who is very helpful to Astrologers. Many astrologers do the Karnapishachini Mantra to get the power to help them.

Also isn't ucchadanam, maranam, sthambanam and vaseekaranam a classification of the keralites? (I have read about this, but dont know about its origins) These are standard Mantric prayogas given in mantra Sasthras.