These natures are calm, docile, modest, and timid. Only 4 natures are possible for 31/31/31/31/31/31 Pokémon caught in generations 3 & 4 (exceptions below). If you choose the former then it really doesn’t matter what nature you choose if you want it to look legitimate than you should consider that: This part can either be extremely simple, or a little complicated depending on if you want your Pokémon to appear legal or legitimate.
Now we know he is only available at one level 30.