Trina is a cruel, stuck up 16 year old girl with anger issues. She holds a deep hatred toward her brother Corey and his band and often tries to goes out of her way to destroy them. She thinks that his band is annoying and nothing more than a waste of garage space that she could be using as her own private bedroom. Outside of her relationship with Grojband, 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 always tries to make him fall in love with her but she is always failing at this, (mostly related to Corey and the band ruining this for her). Whenever Trina gets angered enough, she takes out her anger by writing in her diary whereas she jets up into the air on a geyser of flames and lava and writes in her diary which causes flames to come out of her pen. This is called "Diary Mode". Trina is unaware of the fact that she does this as she forgets it every time she exits diary mode. She is also unaware of the fact that Corey is always stealing her diary and using her diary entries for lyrics, even though he insists that he uses them for inspirational purposes only.
Trina is a very sensitive and trigger-happy girl who is always seen yelling and getting mad over little things. She seems to insult, hurt, abuse, satirize, ridicule, and just be mean to everything and everyone around her to take out her anger. She mostly does this to her friend Mina, who she treats like a slave. She forces Mina to do whatever she wants and always treats her like dirt instead of thanking her. Although it may seem as though Trina is mad all the time because there are bad things happening to her, sometimes Trina seems to get mad and be mean even when nothing has happened to her, which is the reason she really has no friends. Trina hates her brother Corey and his band with a burning passion. She is always seen trying to destroy his band and ruin everything for them.
Trina Riffin has had many alter egos throughout the series which are usually her going in disguise or an inner personality of her's coming out and changing her character entirely.
In the episode Math of Kon, Trina was revealed to have a secret alter ego called Trigonometrina. Trigonometrina is expressive of Trina's inner personality of a nerdy, math geek. What Trina did was dress up like a stereotypical nerd and change her hairstyle and clothing and wear big glasses over her face and go by a different name so that nobody would know Trina's secret. She was really good at keeping this secret from everyone and not even Mina or Corey knew about it. Trigonometrina was best friends with Mina and when she interacted with her, she was very nice to her and she would go along with the things she did and not get mad at her like she usually does. At the end of the episode, Corey figured out her secret and revealed to everyone that Trigonometrina was really Trina in front of the entire school. Trina was extremely humiliated by this and she freaked out so much, she went into diary mode and passed out, despite the fact that everyone was cheering for her. Because of the events of this, it's unlikely that Trina still uses this alter ego.
Quincess Trina Edit
In the episode Dreamreaver Part 2, within the confines of Trina's mind, Trina was shown to have a magical dream world where herself was portrayed as a beautiful and beloved, goddess-like queen/princess who rules over all of the dream world named Quincess Trina. This alter ego was never expressed outside of herself, but it was expressive of her aspirations and ambitions of popularity in the world.
In the episode Dreamreaver Part 2, Grojband went inside of Trina's mind and found a repressed personality of her's locked away in the prison deep down in her mind. This was a girl named Katrina who served as an inner side of her personality. Katrina was a girl who was treated like a criminal in Trina's dream world. She was expressive of Trina's nice side of her character which she never lets out. Katrina was a girl who really loved Corey and would be respectful and joyful about everything. She was even respecting Quincess Trina when she locked her in prison as she was seen refraining from escaping even though she could do it whenever she wanted because of her obedience. It wasn't until Corey and the band came along, who made her become more rebellious and escape prison, making her stand against Quincess Trina and Mirage Band as well as aiding Grojband in taking down Quincess Trina's empire. This alter ego, was expressive of Trina's personality from a long time ago. When Trina was younger, she was nicer and went by the name of "Katrina" and she loved her brother and was nice to everyone. Some unexplained event that occurred at some point in her life must have demented her personality and made her become the angry, hateful egomaniac who we know her as today. Trina compressed this nice personality of her's because of this and always unleashed her inner evil to make herself popular. Since then, Katrina has been contained in a dark prison so that she doesn't ruin her popularity.
In the episode Super Zeroes, Trina got extremely angry when she saw that Grojband had become a band of fake superheroes that everyone believed was real. She wanted to prove that their team was fake, so she dressed up as a supervillain named Stiletto and caused a real problem that they would never be able to fix. However, they actually did fix it and they defeated her in the process. The whole time, her identity was kept a secret, but she was so furious when she was defeated, that she burned her costume in a diary mode rage and went back to being Trina again. It is unlikely that she'll ever go back to being this alter ego again.
Gucky the Troll Edit
In the episode A Knight to Remember, the Bonkerton Comet switched Trina and Mina's personalities, making Trina a kindhearted, fearful pushover who became Mina's dedicated slave. Trina would stay very quiet and would obey all of Mina's commands as she flawlessly served her hand and foot. Shortly after the personality switch, Trina began cosplaying as a servant of Mina's (or Princess Prettina's) known as "Gucky the Troll". Gucky the troll was a disgusting, creepy, hunchbacked goblin who was basically the same thing as her Mina personality. At the end of the episode, the last flash of the comet happened, turning everyone back to normal again and Trina was extremely humiliated and not to mention, enraged at Mina for what she did to her during the personality switch, so she unleashed a on of fury at her and attacked her with a broom. It is extremely unlikely that she'll ever go back to being this personality again, unless the next occurrence of the Bonkerton Comet happens.
In the episode Ahead Of Our Tone, Trina's mind was taken over by a Blab Tap which gave her complete and total control over everyone else who used it simply by using her mind. She transformed into a villainous cyborg mastermind and she referred to herself as "Sparklebrain" and she ruled over all of Peaceville with an iron fist for a year. She made her house her supreme empire and she lead all of the citizens of Peaceville (sans Grojband and Nick) as her army. At the end of the episode, Corey and the band defeated her by overpowering the network of the Blab Tap and breaking everyone free from her mind control, putting an end to Sparklebrain forever.