How much or how widely energy has spread out is measured in Entropy.
Entropy is often called "disorder", "chaos". But Entropy is very different from macroscopic messiness.

Say if I take a deck of cards arranged by value and suit the entire deck. But if I take the deck and shuffle it, that is disorder it, I haven't actually increased the deck's entropy because nothing about the deck of cards' energy is different then it was before. However, entropy in the greater world around us has increased because in order to shuffle the cards my body, has to do work. It has to take energy concentrated in my cells and change and disperse that energy into kinetic energy, movement and a little bit of heat from my body and the cards friction, and a little bit of sound energy- the rustly noise.

So here's your real legacy. Your contribution to the universe growing entropy. No process will ever be able to undo the net created in entropy you accomplish in your life. History may forget you, or misinterpret your accomplishments, or what you stood for. the ripples you leave behind may get redirected, but the universe will never be able to forget the entropy you add. That's the law.
The Second Law of Thermodynamics.