Trina Riffin is the main antagonist in the show. She is the 16 year old older sister of Corey and is always trying to destroy Grojband because she hates it with a burning passion. She has severe anger issues which helps Grojband write a good song in the end of every episode of Grojband. They enrage her big time and she writes about it in her diary. They get it from her and put her words into lyrics.
As seen in the episode Indie Road Rager, Trina has hated Corey ever since they were little kids and they have been sibling rivals ever since. Trina was also shown to be afraid of puppets due to an accident that happened to her when she was a little kid which was shown in the episode No Strings Attached. Trina has no friends except for her best friend Mina who she acts very abusive toward. Trina treats Mina like a slave which is mostly out of her anger issues. Trina also has a secret crush on a boy named Nick Mallory. She is always trying to make out with him and use their first kisses together but is always failing. Trina's got no clue that Corey's stealing her diary and thinks his annoying little band is nothing more than a waste of good garage space. A garage she could be using as her own private bedroom.
Trina has pink hair and a purple head band and a white shirt, a purple skirt, and shoes.
An emotional 16 year old girl. Who seems to insult, hurt, abuse, and just be mean to everything and everyone wether their nice to her or not.
- Corey Riffin - Corey is Trina's younger brother and arch nemesis. They have a very bad sibling relationship. Corey annoys her, and she's generally rude to him. But, if it wasn't for her and angsty diary entries, the band's lyrics wouldn't be any good. She always tries to ruin grojbands gigs, but fails!
- Kin Kujira - Trina Hates Kin and all of his stupid Geekiness. She hates how he's a nerd and how he is a member of her most hated band in the world "Grojband"
- Kon Kujira - Trina Hates Kon because he's fat, eats way too much food, farts alot, and is a member of Grojband.
- Laney Penn - Trina Hates Laney because she is a member of Grojband. She think's Laney's a boy.
- Mina Beff - Mina is a friend of Trina. Mina tries her best to stay on her good side. But in actuality, she gets on Trina's nerves. She is always being abused or neglected by Trina and gets treated like a slave by her.
- Nick Mallory - Trina has a crush on Nick. When he's around her, she get's dreamed-out and lovestruck.
- Carrie Beff - Trina likes Carrie because she hate's Grojband and is their enemy and rival band and wants them dead.
- Kim Kagami - Trina likes Kim because she hate's Grojband and is their enemy and rival band and wants them dead.
- Konnie - Trina likes Konnie because she hate's Grojband and is their enemy and rival band and wants them dead.
- Lenny Nepp - Trina likes Lenny because she hate's Grojband and is their enemy and rival band and wants them dead.