Catherine (Japanese:カトリーヌ Katorīnu) is the head judge for Mars' Brightest.
She has a short lilac hair. She also has a mole under her lips
She seems to be brutally honest when giving judgements and doesn't mince her words.
Catherine was introduced as one of the judges at Mars' Brightest Competition. After the Fire Brothers, she was happy that they were still alive. After Pyotr performed too, Catherine then started judging the two performers. She commented that Fire Brothers performance made her forget their age, but they felt stuck in the past and had not evolved. For Pyotr she was thinking he wasn't serious, but his performance made her realize that wasn't the case and announced Pyotr as winner of the round.
Catherine was impressed by OG Bulldog's rap and opera mix, but after Carole Stanley and Tuesday Simmons performed too and she had to judge, she revealed OG Bulldog persona was fake and showed an interview with his grandma. She found Carole and Tuesday to be the most ordinary and bland of all contestants, but was happy to hear a song not by an AI and announced them as winners.
GGK was facing the Mermaid Sisters. Catherine asked GGK why he wrote she was 13,800,000,022 years old, but GGK explained it was due to her being connected to the universe. As Catherine didn't understood it, they let her start singing. When the Mermaid Sisters started performing their song, Catherine couldn't listen for the whole song and stopped them, announcing GGK as winner. As she told them that their song had great harmony, but bad lyrics. The Mermaid Sisters got angry, claiming that the lyrics are the true words for them and attacked the jury table.
As the Cybelle vs Angela Carpenter round came. Catherine was impressed by both and had a hard time deciding the winner. She told Angela she was thinking she was just a model, but now no one sees her as just a model and congratulated her on the win.
In the second round, GGK faced Angela Carpenter. Catherine considered this being the closest round, but GGK did the same thing as in her first performance, while Angela showed a different side of her and announced Angela as winner.
After the Pyotr vs Carole & Tuesday, Catherine mentioned that it was again close result and that not all judged agreed on the outcome. She congratulated how good Pyotr was and his dancing. For Carole and Tuesday, she said they were still amateurs and has some issues this time, but they managed to express their feelings during their song and that they stole her heart, so she announced them as winners.
In the finals, Catherine was amazed by Angela's song. When Carole and Tuesday showed up, she wanted to disqualify them for being late, as those where the rules. Benito agreed, but still wanted to hear them sing. The girls were fine with being disqualified, but still wanted to perform and after Angela also expressed her desire for them to sing, Catherine decided to make an exception and allowed them to sing.
After their perfomace, the crowd was cheering for them. Catherine said they can't reverse the disqualification and announced Angela as winner, but as special exception, she announced all of them as winners and would reward Carole, Tuesday and Angela a chance to debut.