Real Dictionary

descend
verb: If a large group of people arrive to see you, especially if their visit is unexpected or causes you a lot of work, you can say that they have descended on you.
verb: If you descend or if you descend a staircase, you move downwards from a higher to a lower level.
verb: If you say that someone descends to behaviour which you consider unacceptable, you are expressing your disapproval of the fact that they do it.
verb: When a mood or atmosphere descends on a place or on the people there, it affects them by spreading among them.
verb: When night, dusk, or darkness descends, it starts to get dark.
verb: When you want to emphasize that the situation that someone is entering is very bad, you can say that they are descending into that situation.

descend in American English
to move from a higher to a lower place; come down or go down
intransitive verb: to go or pass from a higher to a lower place; move or come down
transitive verb: to move downward upon or along; go or climb down (stairs, a hill, etc.)

descend in British English
to move, pass, or go down (a hill, slope, staircase, etc)