Death is ultimate poverty. You lose everything you have and everything you are, all at once. And this ultimate loss is not avoidable nor reversible. And sometimes it comes without warning.
So it's quite normal to fear death. My trick to not fear death too much is this: perhaps in theory I own what is mine, but in practice I just have some assets that were lent to me, and that will be lent to others after my death. I see myself as just some manager of what I have.