Lillie is a young girl with green eyes and long light blond hair, with two braids at each side of her face. She wears a large white hat, with a blue ribbon around it. Lillie wears a white dress with transparent outlines, a pair of long socks and white shoes resembling ballet flats. She also carries a round bag with a Poké Ball design on both sides.
As later revealed, Lusamine made the choice of Lillie's dress for her, likely with the intent of resembling a Nihilego given her obsession with that species of Ultra Beast. After realizing her mother is too far gone to listen to reason, she changes her outfit to a white sailor-like shirt with a blue ribbon and a skirt with a light blue line. She stops wearing her hat, instead restyling her hair as a ponytail tied together with a braid. She also wears a pink backpack with a white ribbon.
Lillie is a mysterious girl who assists the professor for personal reasons. She's not fond of making Pokémon fight in battles, but she loves reading and has devoured many books. Lillie was revealed to have taken a Cosmog from her mother, and along with Kukui and Burnet are studying the Cosmog and its secrets. Lillie will play an important role in the story of Pokémon Sun and Pokémon Moon.
Lillie loves to shop and read books. When she is traveling with the player character, she is usually exclaiming to do some shopping of her own, and in cities would tell the player character that she got lost and ended up buying outfits in a shop. Lillie is always getting lost, and the player character has to help her. This happens usually because Lillie is trying to avoid Team Skull grunts, as she is not a trainer, and ended up going in the wrong directions trying to get away from them.
Lillie originally had a close relationship with her mother, as she mentioned sleeping in Lusamine's bed as a child. However, over time, Lusamine started becoming insane, and grew even madder when Gladion escaped Aether Foundation two years before the story begins. She became unbearable to Lillie, so she left as well. When the player character and Lillie meet Lusamine in Ultra Space, she gets the courage to yell at Lusamine for being terrible for trying to control her and stating that "children are not just things that belong to their parents". After Lusamine gets separated from Nihilego, she regains some of her sanity back and touches Lillie's cheek. Lillie eventually decides to travel to Kanto to find Bill so that he may give her the cure for Nihilego's poison. Lillie also decides to go to Kanto to become a true Pokemon Trainer so that she may earn badges and meet and catch lots of wonderful Pokemon.
Sun and Moon Demo
Lillie can be found near the Ten Carat Hill entrance on Saturday evenings staring at the night sky with something in her bag.
Lillie is first seen in the intro of the game three months before the story takes place, fleeing from Aether Paradise. She is cornered by three employees, but Cosmog teleports them out of the paradise. She is found by Professor Burnet at the beach and she tells her husband. Professor Kukui takes her in and gives her a place to stay.
Three months later, Lillie is encountered going to the Ruins of Conflict. Cosmog escapes her bag and she gets worried. The Cosmog, nicknamed Nebby, is suddenly attacked by three Spearow and then the player character arrives. She gives the player character the task of saving Cosmog. While protecting Nebby, the bridge breaks and Tapu Koko saves the player character. She thanks the player character and asks if they can lead her down because she is not a trainer. She then introduces herself as the assistant of Professor Kukui. When they both get back to town, Lillie tells Hala and Kukui what had happened and the player gets to choose their starter Pokémon.
Once the player character defeats the Elite Four, and it at the Festival, Lillie asks the player character to sneak to the Ruins of Conflict with them to thank Tapu Koko for saving the player character. After the player character battles Tapu Koko, they both head back to the Festival. The next scene shows Hau running into the player character's house and telling him/her that something is a disaster. The player character and Hau arrive to the dock to learn that Lillie is leaving for the Kanto region to help her mother and to become a real Pokémon trainer and meet lots of different Pokemon of the Kanto region. The player character and Professor Kukui wave goodbye as Lillie sails off. However, Hau is still upset Lillie left. During the credits, it is revealed that the main characters of the story have sent Lillie a package with photos of daily life in Alola and a letter, along with an Island Trial charm. Lillie is grateful for the package and says how everyone's smiles led her to Kanto. Another cut scene shows the opened package with a picture of the player character, Lillie, and Hau together when Rotom took their picture on their way to Hau'Oli City.
- Main article: Lillie (anime)
- Main article: Lillie (Adventures)
- Lillie is revealed to own a makeup bag and lens case.
- Lillie calls her new outfit her "Z-Powered form".
- Lillie's diary can be read by the player character after he/she defeats the Elite 4. According to her diary, she mentions that Alola had no "gym leaders" or "an Elite 4". This may mean that Lillie originally came from a different region other than Alola, as she is familiar with the concept of gym leaders.