Brahm Rakshas is actually the spirit of a Brahmin, a dead scholar of high birth, who has done evil things in his life or has misused his knowledge, who has to suffer as a Brahm Rakshas after his or her death. The earth-bound duties of such a scholar would be to disperse or impart knowledge to good students. If he did not do so, he would turn into a Brahma Rakshas after death which is a very fierce demonic spirit. The word Brahm means Brahmin and Rakshas, a demon. As per ancient Hindu texts they are powerful demon spirit, who have lot of powers and only few in this world can fight and over-come them or give them salvation from this form of life. It would still retain its high level of learning. But it would eat human beings. They have the knowledge of their past lives and vedas and puranas. In other words they have qualities of both Brahmin and Rakshas.
It is said that the 7th century Sanskrit poet Mayurbhatta, who composed the noted Surya Sataka (one hundred verses in praise of Lord Surya) was troubled by Brahmarakshasha. He was doing penance at famous Deo Sun Temple located at Aurangabad district of Bihar. Brahmarakshas was living in the Peepal tree under which Mayurbhatta was doing penance and creating the verses. It was repeating the verses pronounced by Mayurbhatta, disturbing him. In order to defeat him Mayurbhatta started to pronounce words through nose. Since Brahmarakshasas or other spirits do not have a nose it was defeated and left the tree, which immediately turned dry. After the spirit left Mayurbhatta could peacefully create the hundred verses in praise of Surya, which cured him of leprosy.
Brahma-Rakshas were a regular feature in old Indian stories like Vikram and Vetala, Panchatantra and other old wives tales. As per these stories, Brahma-Rakshas, were powerful enough also to grant any boon, money, gold, if they became pleased with any person. In most of the stories, they are depicted as huge, mean and fierce looking having two horns on head like a Rakshas and a Choti like a Brahmin and usually found hanging upside down on a tree. Also a Brahma Rakshas would sometimes eat human beings in stories.
In many Hindu temples, especially in Central India like Maharashtra and South India like Kerala you can find idols of Brahm Rakshas in outer walls and are generally offered pooja, respects and an oil lamp is lit on regular basis in front of their idols. There are many temples, where they are also worshiped as demi-gods, like in Malliyor Temple of Kottayam District of Kerala, it is customary to take permission from Brahma Rakshas before commencing the construction activities. Further, at Thirunakkara Shiva Temple also in Kottayam in Kerala, there is a separate temple for Brahm Rakshasa. There is an interesting story about why the Brahma Rakshas temple was built here. One person called Moose was a great friend of the king. The king was not known for his beauty but his friend Moose, was very handsome. The queen fell in love with this friend knowing which the king ordered his servants to kill Moose. Instead of killing him the King’s servants killed the junior priest of the temple (keezh Santhi). The wife of the priest became a Brahma Rakshas and started troubling every body. So the king built a temple for her. For a long time afterward women did not prefer to enter this temple. Further, it is said that at Madikeri the Omkareshwar Shiva temple was built by king to ward of evil caused by Brahm-Rakshasa. At Shringeri, the Malayala Brahma Temple is of a Brahma-Raskshas. Similarly, there is separate temple for Brahma Raksha within complex of famous Kandiyoor Shiva Temple near Mavelikkara.In Njarakkal in Kerala there is an 800-year-old Bhagavathi temple where the other temples include Shiva, Nagaraja, and Sree Brahmarakshas. In Palakkad district of Kerala at mundakottukursi near Shornur, a Mana ( meaning the family house of the Namboodri Kerala Brahmins) called "Akathekunnathu Mana" where people worship Brahmaraksha and do some vazhipadu or rites to get rid of haunting and troubles created by the spirit of Brahmaraksha.
There are different plays like Kaisika Natakam in South India where artist play role of Brham-Rakshas.
Further, there are mention of Brahma-Rakshas also in Jainism in their scripts and stories.
In countries like Thailand, Cambodia and also Java whose culture has large influence of Hindu heritage and Sanskrit language, we can find little shrines elevated on poles. These are erected in neighborhood of every house in veneration of nature spirit. These spirits were identified in early times with Hindu deities or Sanskrit names like Brahmarakshsa, Sri Shikeshwara (Shiva), Sri Champeshwara (Krishna) and others.
In 2014, Vikram Bhatt, has made India's first 3D creature horror film, titled 'Creature 3D', in which his creature or demon is a Brahmarakshas - a mutant from Indian mythology. However, his demon who is a Brahma Rakshas, will not be a copy of its ancient Idol, in order to avoid hurting any religious sentiments. Due to this, Vikram Bhatt came up with his own imaginative take on the creature by using special effects in this film. In the film the Brahmarakshasha is depicted as a 10-feet tall animal like creature, which has a swishing tail, carnivorous teeth and nails. It is in the same league as the Yeti.
In July 2016, Zee TV announced the weekly horror based television series titled Brahmarakshasha—the story of a resurrected Satan.