Elementalist Lux doesn't know how Elements work
I want to try to break this down and figure out Riot's logic;
You start as Light
Fire - Water = Dark Earth - Wind = Dark
Riot says these "cancel each other out so they're Dark" which doesn't really make much sense, but okay
Fire + Wind = Lightning? Fire + Earth = Lava/Magma? Earth + Water = Life/Flora? Water + Wind = Ice