Caesar is not really portrayed in a bad light in the play. However Shakespeare does stress certain qualities in his character which help to bring about his downfall. From the first he is shown to be quite conceited, grandly speaking of himself in the third person: ‘Caesar is turned to hear’ (I.ii.17)
Generally he behaves as though he were untouchable, far superior to others. This makes him over-complacent in the face of any danger. For instance, although he does have Cassius’s measure, realising that he is dangerous, he says that he himself ‘is not liable to fear’ (I.ii.198). He dismisses signs and warnings from others, like the soothsayer. He even says, when his wife Calpurnia tells him about her dream that makes her afraid for him, that he is like the stronger of two lions born aas twins:
Danger knows full well
That Caesar is more dangerous than he.
We are two lions littered in one day,
And I the elder and more terrible;
And Caesar shall go forth.(II.ii.44-48)
And, just before his slaying, he appears more self-important than ever praising his own qualities:
I am constant as the northern star;
Of whose true-fixed and resting quality
There is no fellow in the firmament. (III.i.60-62)
This perhaps has the effect of lessening the audience’s sympathy for him somewhat, at the crucial moment of his assassination.
In this play, Caesar is not yet the capricious tyrant that Brutus fears he might become; but his overbearing arrogance and self-conceit, as well as making him a less attractive character, help to bring disaster down upon his head.