no this has nothing to do with naruto i'm doing for a comic/manga making at homeBy "Darkness" I assume you mean Yin. Yin and Yang are the basis for non-elemental techniques. Anyway, there is no strongest single element. It varies upon the user: skill, chakra input, etc.
Each basic element can beat another and lose to another
Earth beats fire
Fire beats wind
Wind beats lighting
Lighting beats earth and water
Water beats fire
I guess lighting is stronger cuz it beats 2 elements while rest just beats one
Fire is the weakest cuz it has two weaknesses ..