Some natures dont decrease or increase any stats the answer isn't true i think none of them are right I think it should be that they effect their favourite and disliked flavor because they do some.Example: Hardy-It doesnt increase or descrese any stat Let's look at another nature: Lonely-increases Attack,lowers Defense,it dislikes the flavour Sour and its favourite flavor is Spicy. So I think both statements are equally wrong and right someone could argue with me that natures are known for the fact that most of them increase and decrease stats but i dont think this question should exist because it can never be fully right.
Natures are very important to Pokťmon battling. A Pokťmon being raised in a useful stat for that Pokťmon in exchange for a loss of a not-so-important stat to that Pokťmon is needed to get the upper hand in competitive battling. There are 25 natures, covering all of the possible stat-up and stat-down situations. Five of these natures do not affect the stats of a Pokťmon whatsoever because they raise the same stat that they decrease.