when you export a game to an .exe file, will the empties be deleted?
EX. FPS empty is a bullet add object. so if I export it will the empty disappear?

No. All your data should be right where you leave it.

The empty is invisible in the game engine, but it “functionally” exists:
For example one or more objects can be parented to it so they all do rotate when the empty rotates.
And the .exe file reflects this behaviour.

ok thanks guys (and girls) ! helped me out a lot