There are many different kinds of writing in the Bible.
There are, for example, songs and poetry and letters and law and histories. The Book of Esther is a history in the sense that it records events that actually happened, but it is told in the form of a story. The book is a short narrative of events that occurred in Persia (modern day Iran) and it features character and plot development, suspense and climax.
One of the marks of a good story writer is that he or she will “show, not tell.” That is, rather than simply dictating conclusions about events or characters, e.g., “the king was a thoughtless man,” the good story writer will unfold the drama before the readers eyes by describing action and will let the reader form his own conclusions. I think the writer of the Book of Esther was on to this.
Never in the story are we directly told anything about the character of King Xerxes, but as we read the story and see his actions and decisions, we may come to some pretty definite conclusions about him.
We see him first at a drunken party – one that he has put on to show off his wealth and power. The writer gives us very particular details about the opulence of the setting and the extravagance of the event. This party went on for days and there were servants with trays of drinks at the elbow of every guest. From this we may get some inkling that Xerxes was a vain man – impressed with himself and intent on impressing others.
The first decision we see the king make involves his relationship with his wife