I think in this situation you could just list their strengths (as how a character can win) and weaknesses (how it can lose).

The goal is not to win or lose after all but to set up the scene for other people to continue the same story according to some common logic, so in the character description, you need to provide some kind of algorithm on how that character will behave in various situations.

I suggest to avoid any boring numeric systems, but just write a short story about that character, listing strengths and weakness and some examples of their behavior or achievements.