According to the Brahmand Puran there are different types of Rakshasas, to be precise, seven and their orign is indicated by their names such as Paulastyas, Agastyas, Kaushiks etc.

In his previous birth Rāvaṇa was Hiraṇyakaśipu. That Rākṣasa ruled as king for thirteen sets of four Yugas......Mahodara, Prahasta, Mahāpārśva and Khara were the sons of Puṣpotkaṭā. She had a daughter (named) Kumbhīnasī also Triśiras. Dūṣaṇa and Vidyujjihva the Rākṣasa are remembered as the children of Vākā. There was aḍaughter also named Anupālikā.

Thus these ten Rākṣasas, the descendants of Pulastya (CATEGORY 1), were of very cruel activities. They are of very terrible pursuits, ever since their birth. All of these were unassailable even to the Devas. All of them had acquired boons. They were heroic and they were accompanied by sons and grandsons.

Aiḍaviḍa (i.e. Kubera), the descendent of Pulastya, who was Savyapiṅgala (? Tawny-coloured in the left side) became the king of all Yakṣas, all those Rākṣasas who were the descendants of Pulastya, and of all those cruel Brahmarākṣasas belonging to the families of Agastya and Viśvāmitra who still carried on the study of the Vedas and who performed regularly penances and holy rites.

The other three groups of Rākṣasas were the performers of Yajñas. They were Yātudhānas, Brahmadhānas and Vārtās (CATEGORIES 2, 3 & 4). They were moving about during the day time and they were not nocturnal wanderers like other demons. Their four groups are remembered by the wise (learned men).

So it seems there were some Rakshas tribes that followed the Vedic injunctions and roamed around in the day time while others were night-dwellers and opposed to the Vedic teachings including Ravan and descendants of Agastya and Vishwamitra!

They were Niśācaras (moving about at night), They were Paulastyas (descendants of Pulastya), Nairṛtas, Āgastyas and Kauśikas (CATEGORIES 5, 6 & 7 Paulastyas were already covered). Thus it is remembered that there were seven classes (communities) of those Rākṣasas. I shall describe their form and features inherited by them naturally.

The next verses give a detailed description and it appears that irrespective of their origin the various groups had a lot of common features in their physical appearance as well as habits:

They are tawny-coloured and have round eyes. They have big bellies and huge bodies. They have eight-curved fanglike teeth and pikelike ears. Their hairs stand upright. Their mouths appear as though slit open upto the ears (on either side). Their smoke-coloured upright hairs are like the Muñja grass. They have large thick heads shedding bright lustre. Their thighs and forearms are short. Their faces are copper-coloured. Their tongues and lips hang down. Their brows appear dangling. Their noses are thick.

They have blue (black) limbs with red necks. Their eyes are majestic and they appear terrible. Their voice and tone are extremely terrible. Their calves are hideous and rolled up. They are stout and have prominently protruding noses. They are firm and have sturdy bodies like rocks. They arc cruel and terrible ever since their birth. Generally they are consistent in their activities.

They put on (ornaments like) earrings, armlets and coronets. They bedeck themselves in diverse kinds of ornaments. They wear many kinds of garlands and use all types of fragrant scents and unguents. They are remembered as habitual eaters of cooked rice, meat and even human flesh. Thus is remembered the similarity in forms and features of demons by learned men. They are unequalled in strength, intelligence and ability to fight using the deceptive power of Māyā (or black magic).