What do the phrases, "the die is cast" and "crossing the Rubicon" mean?

The die is cast means an event has happened or a decision has been taken that cannot be changed. It is also a variation of a Latin phrase attributed by Suetonius to Julius Caesar on January 10, 49 BC, as he led his army across the Rubicon river in Northern Italy.

Today, the phrase crossing the Rubicon is an idiom that means to pass a point of no return.

It is c because it shows how the author is stating their own oppinion about the protagonist