All in all, Alexander is larger than life in both behaviour and size. He tells Waver once, "Food, sex, sleep, and war! What ever you do, you must do it to the fullest. That is the secret of life." Alexander follows this philosophy to the T in everything he does, whether it be leading his army, formulating a plan of attack against the other summoned servants, or playing video games.
Like most of the servants in Fate/Zero, Alexander was a leader, but did not work alone. His greatest attack, known as a Noble Phantasm, actually summons his former warriors in a reality marble-- each of whom is individually a heroic spirit, but chooses to serve Alexander. This is one of the best examples of how Alexander works; he is constantly on the look out for allies in the interest of conquest, dividing the spoils of his greed. Though he fought at the front of his army always, he never doubts his warriors had a hell of a hand in his victories. He considers the strength of a king to be that of those who stand behind him, telling Arturia at some point that her belief that a king must stand alone is an idealistic, martyr-like folly. A tyrant though he may be, he knows the merit of a real reward. His intent was to wish to be human again should he have gained the grail; had he known the grail was corrupt, it can easily be assumed he would not recognise it as a treasure worth its toll and likely would have joined in the effort to destroy it. This is the kind of man Alexander is; he can discern the true value of a victory, the power of an ally or enemy, and the worth of a dream. He will follow through on everything, doing it to the fullest. He's reliable in that sense, and it likely explains why people are so quick to trust him.
He is a proud individual, but his pride is not easily damaged; he is confident. He has an ego, but it is without doubts. Even in being defeated by Gilgamesh he is not without victory; he gained a battle that "made [his] heart dance". It is adventure that truly inspires Alexander, and he believes he will always come out victor- but he is not foolhardy or deluded about it. He is strategic, learns from the defeats of his enemies, and though he puts forth a personality even Waver believes is foolish at first, Alexander is clever in most respects. Still, he won't always make the 'wisest' or safest of choices- not if the other choice is more fun or enjoyable. After all, the best and fullest way is not always the easiest and safest one; it is the one of grandeur and adventure, where a risk can be taken and conquered.
Revision/addition to personality section
Like most of the servants in Fate/Zero, Alexander was a leader, but did not work alone. His greatest attack, known as a Noble Phantasm, actually summons his former warriors in a reality marble-- each of whom is individually a heroic spirit, but chooses to serve Alexander. This is one of the best examples of how Alexander works; he is constantly on the look out for allies in the interest of conquest, dividing the spoils of his greed. Though he fought at the front of his army always, he never doubts his warriors had a hell of a hand in his victories. He considers the strength of a king to be that of those who stand behind him, telling Arturia at some point that her belief that a king must stand alone is an idealistic, martyr-like folly. A tyrant though he may be, he knows the merit of a real reward. His intent was to wish to be human again should he have gained the grail; had he known the grail was corrupt, it can easily be assumed he would not recognise it as a treasure worth its toll and likely would have joined in the effort to destroy it. This is the kind of man Alexander is; he can discern the true value of a victory, the power of an ally or enemy, and the worth of a dream. He will follow through on everything, doing it to the fullest. He's reliable in that sense, and it likely explains why people are so quick to trust him.
He is a proud individual, but his pride is not easily damaged; he is confident. He has an ego, but it is without doubts. Even in being defeated by Gilgamesh he is not without victory; he gained a battle that "made [his] heart dance". It is adventure that truly inspires Alexander, and he believes he will always come out victor- but he is not foolhardy or deluded about it. He is strategic, learns from the defeats of his enemies, and though he puts forth a personality even Waver believes is foolish at first, Alexander is clever in most respects. Still, he won't always make the 'wisest' or safest of choices- not if the other choice is more fun or enjoyable. After all, the best and fullest way is not always the easiest and safest one; it is the one of grandeur and adventure, where a risk can be taken and conquered.