Do you know that Lord Shiva is also called the Bhutnath? When he was getting married on Mahashivratri, when his bharat was going towards the Himalayan Parvat to get married to Parvati, everybody joined his bharat. All the animals, all the living things, all the devas, including all the bhuts. Yes, you heard it right. So all the spirits, all the bhut were also part all the rakshas, they all were part of the Shivji Bharat