Lillie is a girl who loves Pokémon but is unable to touch them after moving away to another mansion with her mother and brother. Upon her return, she inexplicably was frightened of Pokémon and will either jump away or froze like a statue though some feel that she is terrified of them. Despite her fears, Lillie loves to leave food out for various Pokémon to eat. Her knowledge of Pokémon is top notch. Lillie was so scared of touching Pokémon that she had to wear a suit to ride Pokémon.

Lillie decided to take one step at a time to get over her fear of touching Pokémon. Initially, she was only comfortable with her Alolan Vuplix Snowy, but managed to touch Ash's Pikachu without hesitation later on, and even ride a Stoutland without repercussions. However, after her memories came back regarding Silvally saving her, she was able to touch all Pokémon without being scared.

She pays close attention to details, which was shown when she noticed the details in the recording tape of Rotom's and proved Kiawe's innocence.

Lillie is rebellious towards her mother Lusamine upon their reunion and like Brock, she also shows her angry and disdain because of her ditzy behavior and also causes a fell out between the two and became annoyed when she keeps doting on her.