ghost truth or not
When a person dies only his gross body ceases to exist. His subtle-body (consisting of the subconscious mind, intellect, ego and soul, i.e. minus the physical body) however continues to exist and moves on to the other regions of the universe. Refer to the picture below for more detailed view of what we are comprised of and what we leave behind after death.
The superior ghost or a person with high spiritual power (who after death becomes a ghost) does spiritual practice with the intention of gaining supernatural powers so as to play "˜God' and thus has a lot of ego.