Potato

Potato is the final boss of Miiverse Pokemon League 3. A former champion, he is fought after the battle with Shadow Mewtwo in the mountains.

Unlock method
First, you must battle Sak Urai Chu in both the overworld and his lab to obtain Key A and Key B.

Next, you must climb to the top of Mt. LMR. You will need to use both keys that you were given earlier.

Sak will battle you one last time before allowing you to enter the mountain.

Next, you will fight Shadow Mewtwo. You can catch it or defeat it, but it only appears once so you will want to catch it to complete the Pokedex.

After that, you will be able to go to exit the cave through the other end and walk up the steps to battle Potato. He is one of the strongest trainers in the game.

Team

 * Whimsicott
 * Donphan
 * Gengar
 * Chansey
 * Bisharp
 * Gardevoir (mega evolves)