From Bulbapedia, the community-driven Pokémon encyclopedia.
Marilyn (Japanese: マリリン Marilyn) is a character of the day who appeared in Battling a Cute Drama!.
Marilyn is a Trainer who believes only Pokémon she finds to be cute are worthwhile. Beyond that, she prefers things being cuter in their own right, calling Dawn and Brock "Dawny" (Japanese: ヒカリン Hikarin) and "Brocky" (Japanese: タケリン Takerin) respectively, because she believed they were cuter names.
She only believes that a Pokémon is cute if its height is no more than 2 feet and if it has not evolved. Even then, she doesn't consider everything that meets that criteria to be cute, including Mime Jr. and Piplup. Meowth also meets the height and evolutionary standards, although Marilyn didn't even seem to notice Meowth at any point.
After seeing Dawn's Buneary, she fawns over how cute it is (dismissing Piplup as not cute enough), and challenges Dawn to a battle. During the battle, she orders her Cherubi not to attack, in order to stall and keep the battling going so she could witness a "valiant battle". Brock gets irritated by Marilyn's superficial attitude towards Pokémon, and decides to teach her about the inner strength and beauty of Pokémon with a battle.
Marilyn claims her perception of "cute Pokémon" was altered to fit in more with normal convention, because she was teased as a child for believing the cutest Pokémon ever was Shellder, a sentiment none of her friends agreed with.
This listing is of Marilyn's known Pokémon:
Marilyn is in possession of a fourth Pokémon as its Poké Ball is seen, but she replaces it with Shellder instead during her and Brock's battle, making her fourth Pokémon unknown.
- Marilyn dresses in the Sweet Lolita clothing style.
- Another character, Lyra, referred to Dawn as Hikarin in the original version.