Because a Pokémon gaines EV on every stat, EV training just helps increasing the number of points gained for a single value. In short, a Pokémon will gain EVs even in stats it wasn't trained for.
Unfortunately, the box trick was taken out of the game after Generation II, and the only way to change stats after gaining EVs is levelling up.
Natures give your Pokemon stat changes and a personality has well not all natures change stats like Docile nature, personality just makes the Pokemon unique it also sets what kind of pokeblock or poffin the Pokemon likes.
Pokemon indigo does not exist
Stats do change back to normal after you switch out Pokemon. This isn't always a good thing to do because then your opponent grabs a serious advantage. My suggestion is to switch to a Pokemon that won't really be affected by the move that your opponent just used and is most likely to use again.
Pokemon natures represent the growth of that Pokemon and what stats are increased and what stats are reduced.
By leveling up your Pokemon
It depends on the level and stats. And, no Pokemon is ultimate.
1000 is the answer
Evolving a Pokemon drastically changes a Pokemon's appearance (normally, to show they became more mature and stronger.) and highly boosts its stats. This is one of the most important to do to have a strong team.
jeffrey need Pokemon
It is a good virus that hightens stats in Pokemon
there is no toughest it all depends the stats of Pokemon and if you have a type advantige.