Characters are Misty and Charizard from Pokemon Red and Blue.
I always liked subtle size differences like this. Misty is I'd say close to 6'0? Which is actually abnormally bigger for someone her age. I don't know. Maybe I'm over analyzing this sketch, I mean its a sketch after all. Still it's wonderful to see ideas like this.
Ah the whole Charizard is 5'7 thing? Yeah that's pretty much the idea behind this. I never really took Misty's canon height into consideration with this sketch but her being 6'0 in this doesn't bother me.