Thanks excellent sci-fi imagination. I like it.
We assume ourselves try to be stronger and stronger , better and better in the future.
But if failed. we got worse in the future. why ? such as lazy in the present, bad thinking in the present, wast a lot of time in the present, seek comfort , etc. and then, the future ourselves are planning kill you by time travel.
It means tell people, Defeat yourself. To Have Continuous Success, You Must Constantly Defeat Yourself. not defeat others.
If you’re seeking comfort, lazy in the present, the future of you will hate present you and kill present you by time travel.
Another paths is that assume we have a different choices in the present. 1, 2, 3 choices.
How good in the future when we chosen path 1 ?
How about in the future when we chosen path 2 or 3 ?
I noticed the last word “kill you” could be the present you , also means the future you.
I assume that is “the future ourselves”, but it have 3 version of the future ourselves.
So, Which is better, which is strong, which is worse, in the future ourselves ?
It means 1st version of future ourselves is planning to travel back kill 2nd version of future ourselves.
the same 3rd vs 2nd, 3rd vs 1st . 2nd vs 1st.
Well. I never saw like this script sci-fi novel, sci-fi movie. Maybe it could be a interactive novel and interactive movie? 
Brief speaking:
the core mean is Defeat yourself. but there is 2 ways.
- You future defeat present yourself.
- Different future ourselves defeat different future ourselves.