"I'll be fine! I've got Max Repels with me. And I've got you, too..."
Lillie is a supporting protagonist and possible love interest to the player character in Pokemon: Sun & Moon. She's also the daughter of the game's main antagonist Lusamine and sister to the rival character Gladion.
The story begins with Lillie rescuing the Pokemon Cosmog (hereafter known as Nebby) from her mother's organization, the Aether Paradise. She's chased down by Lusamine's henchmen, but makes it to the islands of Alola and teams up with the player character
Lille encounters the player shortly after she comes to Alola. When Nebby is attacked by a flock of Spearow, the player bravely steps in and defends it despite not having any Pokemon at the time. Lillie then stays by the player's side during several key moments in the game such as during the island trials and during encounters with staff from Aether Paradise. In these moments she heals the player's pokemon after any battles.
With her mother's corruption and her brother's absence, Lillie sees the player as the only person she can really trust. This culminates in her giving Nebby to the player once Lusamine is defeated, as Lillie has seen that the player treats their pokemon with love and care.
After the Pokemon League, Lillie decides she's going to the Kanto region to become a Pokemon Trainer so that she can eventually battle alongside the player rather than just tag-along.
Lillie meets Hau shortly after meeting the player character. Hau awkwardly tries to flirt with her whenever they meet but is too shy to follow through on them. His interest in Lillie is also shown as he's visibly distressed when she leaves at the end of the game.