According to Aristotle, "Tragedy idealises—imitates men as better (or higher)—and Comedy caricatures, i.e. shows men as worse (lower) than they actually are." The characters in a tragedy should be lifelike, convincing, acceptable, consistent, reasonable, and impressive. They should be people of better sort.
The four essentials of characterization as mentioned by Aristotle in Chapter XV of the Poetics are as follows :—
1. The Characters must be good.
2. The Characters must be appropriate.
3. They must be true to life.
4. The characters must be consistent.
A character is good, if his words and actions reveal that his purpose is good. Entirely wicked characters, even when assigned minor roles, are unfit for tragedy. Wickedness may be introduced only when required by the necessities of the plot. Wanton or wilful introduction of wickedness must be avoided; and when introduced even wicked characters must be made good in some respects. Wickedness must be mixed up with some good as in actual life.
The characters must be appropriate, that is, must be true to type or status. For example, a woman must be shown as womanly and not manly, a slave must be given a character appropriate to his status, and the king to his kingly status. Manliness would not be appropriate in a woman, and vice versa. If the characters are taken from some known myth or story, they must be true to tradition.
The characters must be true to life. They must have the virtues and weaknesses, joys and sorrows, loves and hatreds, likes and dislikes, of average humanity. It is essential to arouse to feeling of pity and fear in the spectators. If they are not true to life, they would not be able to arouse fear and pity. The characters must be of an intermediate sort, mixtures of good and evil, virtues and weaknesses, like us.
Fourthly, the characters must be consistent. They must be true to their own natures, and their actions must be rational, not rash. There should be no sudden changes in character. If the dramatist has to represent an inconsistent person, then he must be, 'consistently inconsistent.'
And lastly, "The ideal there must be an intermediate kind of person, a man not primarily virtuous or just, whose misfortune, however, is brought upon him not by vice or depravity, but by an error of judgement." Furthermore, he must be a man of'reputation and prosperity'.