The rakshasas are sons of Pulastya (a son of Brahma) and so to speak, they are brothers of the monkeys and the kinnaras:
From Pulastya were born the rakshasas,
the monkeys and the kinnaras.13
Normally they are represented as eaters of men, an example is Hidimba and his sister Hidimbi (or also Hidimba) who wanted to eat the Pandavas and Kunti:
Vaishampayana said, 'Not very far from where they slept in the forest, to rakshasa named
Hidimba lived on a shala2 tree. He was cruel, addicted to human flesh, very brave and very
powerful, malformed, with yellow eyes, and terrible and fearful to look at. He was thirsty and
hungry and was looking around, when I happened to see them. With his fingers extended
upwards, I have scratched the dry and unkempt hair on his head and yawning with his large
mouth repeatedly, looked at them. The evil eater of human flesh, with a huge form and great
strength, smelt humans and told his sister, "After a long time, I will today devour my
Favorite food Anticipating the pleasure, my tongue is moist with saliva. My eight sharp-
pointed teeth are impatient because they had nothing to bite. I will dip them into these
bodies and the delicious flesh. I will attack the human throats and arteries. I will drink
copious quantities of the warm, fresh and foaming blood. Go and find out who are sleeping in
the forest. The strong smell of humans alone pleases me. Kill those men and bring them to
me. They are asleep in our territory and you need not fear. We will both eat a lot of flesh
from these humans the way we like it. Quickly do what I tell you. "O bull of the Bharata
lineage! On hearing his brother's words, the rakshasi quickly went to where the Pandavas
were.
But because Hidimbi fell in love with Bhima, he rebelled against his brother.
The rakshasas grow very quickly, since Ghatotkacha had the form of a young adult, and that was just after birth:
'From Bhimasena, the rakshasi then gave birth to an immensely powerful son. I had a
fearful appearance, with terrible eyes, a large mouth and ears like spikes. His form was
distorted. His lips were brown as copper and his teeth were sharp, with great strength in
them. He had mighty arms, possessed great energy and was born extremely valuable, a great
archer He had great speed, with gigantic size and was a conqueror of enemies, highly skilled
in the powers of delusion. Though born from a man, with great speed and great strength, I have
had nothing human in him. I have surpassed all pishachas and other such creatures, not to speak
of humans. O Lord of Men! Although a child, by human standards, he seemed to be a fully
grown youth
The rakshasas also eat the brahmins, hate them and even ruin their sacrifices.
Another characteristic is that the rakshasas have a prodigious force, since among the rakshasas that Bhima faced a hand-to-hand fight, they gave him a good fight but still they were killed by Bhima.
Next I will give descriptions of Krishna or the War of Kurukshetra to make known the rakshasas that were apart from those that I had already described:
Hidimba, Baka and Kirmira have been brought down by Bhimasena. They were the equals of Ravana and destroyed the sacrifices of brahmanas. Similarly, Alayudha, who used maya, was slain by Hidimba’s son.
However, Hidimba’s son crushed Alambala.
O great king! On seeing this, Duryodhana attacked the rakshasas. He was overcome
by intolerance and gave up all desire to protect his own life. The immensely strong one
released arrows towards the rakshasas. The great archer slew the foremost among the
rakshasas. O best of the Bharata lineage! Your son, Duryodhana, was angry. The maharatha
used four arrows to kill four of them—Vegavat, Maharoudra, Vidyutjihva and Pramathi.
‘“On seeing that all of them had fallen down, Duryodhana was frightened. He spoke to the
extremely terrible rakshasa who was terrible in form. The scorcher of enemies was a great
archer and was skilled in maya. He was the son of Rishyashringa.320 He had earlier become
an enemy of Bhimasena on account of the slaying of Baka.321
Vaishampayana said, ‘The Pandavas lived comfortably on that mountain. When the rakshasas
and Bhimasena’s son
1 had left, and they were without Bhimasena, who had gone to roam around as he willed, a rakshasa abducted Dharmaraja, the twins and Krishna.2 He had
pretended to be a brahmana skilled in mantras and well versed in weapons. Having said this, he had served the Pandavas every day. He lived with the Parthas, covetous of their quivers and bows and waited for his chance. He was known by the name of Jatasura.
Ghatotkacha’s son was handsome and was like a mass of collyrium. As Drona’s son advanced, he checked him, like a king of mountains against the wind. Anjanaparva, Bhimasena’s grandson.
In all, these are the rakshasas that are in Mahabharata:
1- Hidimba
2- Hidimbi
3- Ghatotkacha
4- Anjanaparva
5- Alayudha
6- Alambusa
7- Alambala
8- Jatasura
9- Baka
10- Kirmira
11- Vegavat
12- Maharoudra
13- Vidyutjihva
14- Pramathi
Another fact about the rakshasas is that they strengthen how much darker the night is. During the midnight, the powers of the rakshasas are such, that in Mahabharata Ghatotkacha he became so powerful that he defeated Drona, Kripa and Ashwatthama although before he was very defeated by Drona and Ashwatthama during the day.