As in all Pokemon Games,
The Alola Region too has a number of recurring Supporting Characters you will meet up with throughout your journey. Usually these are either friends or rivals of your Main Character.
Hau
You will first meet
Hau after receiving your Starter Pokemon, a boy who will later become your friend and official Rival. He is very young and carefree with a large appetite, but he too is ambitious enough to challenge and eventually defeat the Island Challenge.
Professor Kukui
Kukui is the Professor of
The Alola Region. Unlike a number of previous Professors, Kukui is much more interactive throughout the entire main storyline. He even loves to
Battle, being the Masked Hero of
Royal Avenue and the last person you must face in order to become
Champion after defeating the Elite Four.
Lillie
When you first meet
Lillie, so much mystery surrounds both her and
Cosmog. However, you will eventually find that she is the sister of
Gladion and daughter of
Aether Foundation Head
Lusamine. She saved Cosmog from
Aether Paradise and her mother, finding her way to the shelter of Professor
Kukui and his wife. She will travel virtually alongside you throughout your entire journey.
Gladion
Gladion is the brother of
Lillie, yet he's not your friend nor a rival. Like Lillie, he ran away from
Aether Paradise after saving a Pokemon the foundation had made and were trying to use similarly to
Cosmog, Type: Null. Unlike Lillie, however, who found her way to the safety of
Kukui, Gladion ended up getting mixed up in joining
Team Skull.