Comments of chapter undefined of Naruto: A Different Reality

No, you are wrong author. we cannot improve our chakra affinities. they are like our natural talents in ninjutsu, where we are strongest. However, anyone can use a jutsu without having the affinity for it! Someone without the fire affinity can use the great fireball! But on the other hand, it will take him a lot more time to learn it, it will consume more chakra... It's just not optimized. Ninjas focus on strengths.