For the role of the God, the person selected should not be wanting in any limb. He should be well informed and should not be too stone or too lean. He must have vivacity, pleasing voice and appearance. Role of Raksasas are assigned to the bulky ones with large bodies and gruff voice resembling the rumbling of the cloud. Furious eyes with knit eyebrows should be assigned the role of demons. Performance of male actors must be in accord with their limbs and movements. Role of kings are given to the ones with beautiful eye, eyebrows, forehead, nose, lips, cheeks, face, and neck. They must be tall with pleasing steps, good behaviour, and wisdom and should have the steadiness of nature. They should neither be fat nor very lean. The same holds good in the assignment of the role of Princes. Role of the Army are assigned to the person who have distinct speech. They should not be too tall or fat. They must be heroic, eloquent and brave. Reasoning ability and presence of mind should be their salient features.
Role can be assigned at the discretion of the director after considering the age and physical condition of the actor concerned. Persons who are dwarfish, hunch-backed, uncouth and odd faced can be engaged in the role of slaves. They should be rather fat with expressionless eyes, small chin, and low nose. Evil nature and deformed body are also marked characteristics of a slave. Rolf of tired persons should be given to someone in utter exhaustion and fatigue. The Bhavas and Cestas (gestures) should be taken into account before the assignment of the role. The natural movements of the people may be good, bad or middling. They can be regulated by the director in charge and the candidate can later represent the Bhavas properly. In other cases also the convention has been laid down. Roles should be assigned after the due consideration of their native places, costumes etc.
No character shall enter the stage in his natural form or shape. The body should be covered with paints decorations and embellishments. Human characters in as much as they are represented on the stage can be classified into three parts, Anurupa (befitting, natural), Virupa (not fitting, unnatural) and Rupanusarini (close by emulative). Women actresses in the role of female characters and man actors in the role of male characters with age etc. befitting the respective roles can be called Anurupa. If a boy plays the part of an old man or vice versa it is an example of Virupa. A man may assume the role of a woman and be successful in imitating the character. This is called Rupanusarini. In the same manner a woman may assume the role of a man. But an old man or a boy should not emulate each other. Bold men with strength and heroism may be employed in the role of reciters and women in the role of singers.
Thus assigning the role to different characters is an imperative part of the Natyashastra.