Lillie is a girl that loves Pokémon, but is unable to touch them because she was attacked by an Ultra Beast.
Gladion was so terrified he wasn't able to save her but Type: Null saved them. Lilie had never mentioned anything about this to
Ash Ketchum or her friends because she couldn't remember as that experience frightened her that badly.
Her knowledge of Pokémon is top notch. She first met Ash at the Pokémon School on Melemele Island when she tried to warn him to avoid the Tauros.
Silvady is a Pokémon that was created to defeat Ultra Beasts.
Gladion didn't want to go into detail about its creation but he explained to
Ash Ketchum that nobody must know about Silvady's existence. After
Lillie was captured by
Faba to wipe her memories again, Gladion's Type: Null broke through its helmet they had been trying to take off to reveal that it was a Silvady. It once again fought
Faba and rescued
Lillie.
Lillie remembered what had happened before and thanked Silvady for rescuing her and gave it a hug, touching it and finally getting over her fear of touching Pokémon now that her memory was restored.