Path of Solitude

After you have reached Daybreak in the game's post game, you will get two new battle modes from Ingo. One of these is the Path of Solitude

The Path of Solitude has you pick just one Pokémon and have you face off against a set team. Each Pokémon has got a specific opponent and the battles are designed to be tricky and work against the Pokémon you are using

When you have completed a Pokémon in the Path of Solitude, you will get a new flag on the Pokédex to show that you have completed it

As you complete with more Pokémon, you will receive more rewards such as Exp. Candy. You will get 3 EXP. Candy L for each first time completion and 3 Grit Dust for subsequent completions. There are also rewards for milestones