The "Red Death" is used as a symbol in this story.  The red death has no pestilence or has never been so fatal or so hideous.  The red death is using an object more than its literal meaning.

The second paragraph is an example of characterization because it describes the prince. It explains his qualities and his eccentricities. It also shows that he doesn't think about anyone but himself.

The last paragraph shows irony.  The irony is showed by the fact that in the beginning the prince and his men were trying to escape the Red Death.  They move into a seculded area that they think the Red Death can never get to.  The Red Death eventually does catch up with them and ends up bringing them to their deaths.