Best Nature for Piplup, Prinplup, and Empoleon in Pokémon Legends: Arceus

gamepur.com:

A Pokémon’s Nature decides what stat boosts and losses a Pokémon will naturally receive — excluding the HP stat. For instance, the Adamant Nature will boost a Pokémon’s Attack stat at the cost of lowering the Special Attack stat. Knowing this, we can take a look at Piplup and its evolutions’ stat pools and see what Nature would be ideal in Pokémon Legends: Arceus. 

Since Piplup, Prinplup, and Empoleon all basically have the same stat pools, with each stat all getting higher at almost the same rate with each evolution, it will be easy to choose a good Nature to strive for with this line. 

The line’s highest stat is Special Attack, with Speed being their weakest point. Knowing this, we can decide what Nature we want. Since the Special Defense stat is so close to matching the Special Attack stat, and the entire line doesn’t need to make much use of the regular Attack stat, we can look at Calm Nature as a potential winner here. This will give us that boost to Special Defense to make it equal to the Special Attack stat that we were looking for, and makes it well worth the drop in the Attack stat. 

An alternative to the Calm Nature, especially if you want to pump that Special Attack stat as high as possible, would be to look at the Modest Nature. This will give us the same losses as the Calm Nature — an affordable hit to the Attack stat, while also powering up the Special Attack to be well above the rest of the stat pool.

Overall, this makes the Calm Nature better if you’re focused on a Special Defense-based build for your eventual Empoleon, or, if you want to lean more into the Special Attack stat, you can choose the Modest Nature to better suit your needs.