Details: One of the fourteen Special Trainers you will encounter at The Battle Tree as a partner in Multi Battle Mode is Lillie. In order for her to join you at the Battle Tree, you must first talk to her in Professor Kukui's Lab. A novice Pokemon Trainer, Lillie prefers to use Fairy Type Pokemon.
Possible Pokemon:
Ribombee (Light Clay): Pollen Puff, Reflect, Light Screen, U-turn
Comfey (Grassium Z): Dazzling Gleam, Petal Blizzard, Grassy Terrain, Floral Healing