Donald Trump may be a narcissist, but since he is not mentally ill in the technical sense, he is not a pathological one. Aristotle would have seen him as entirely normal — a man driven by rage that the world does not see things his way.
For Aristotle, a man becomes angry because of what has been, or will be, done to him. According to Aristotle, Trump’s current feelings would be that he has been belittled and humiliated in an election in which he was by far Joe Biden’s superior. The consequence of that, as Aristotle says, is anger: anger that Biden — whom Trump sees as e.g. ‘inferior, of no account, not fit to rule, disrespectful, forgetful of his name (!)’ (Aristotle) — has defeated him and leaves Trump, the great winner, a loser.
The result, if we follow Aristotle, would be a burning desire for revenge, the pleasing prospect of getting your own back on those who have humiliated you. That was an instinct deeply ingrained in the ancient Greeks. As Thucydides said: ‘Those who think it justified to satisfy the rage in their hearts by taking revenge on their adversaries have law and custom on their side, while retaliation against enemies… is proverbially the greatest of pleasures.’ Indeed, we are told that refusal to take revenge was the mark of the unmanly.
But this creates a problem for Trump — how on earth can he take revenge against a democratic decision? Since, as Aristotle points out, you can only be angry with a man, not all mankind, Trump can hardly ‘pay back’ Biden for winning, let alone 78 million Democrats for voting.