After Obake's demise, Trina enacted her own plans in order to keep her "father's" legacy alive.
Trina appears to be a normal teenage girl, albeit with a controversial streak. In reality, she is an android controlled by Obake, whom she refers to as her father. Under the guise of a bot-fighter, Trina is sent out to gather intel on Hiro Hamada.
When not tending to her mission, Trina acts as an organized thief—despite Obake's disapproval. By hacking into the bots of her competitors and using them to steal from San Fransokyo, Trina orchestrates a crime wave that lets others take the fall while she ends up rich; for Trina, it's a profession that's both lucrative and fun. She's also obtained other knick-knacks such as figurines, which she keeps at her bot station in Good Luck Alley. Obake sees Trina's hobby of "collecting trinkets" as a waste of time.
Trina has a spunky, yet rebellious attitude. She addresses everyone she meets with snark (even her father) and acts in a very self-assured manner. Her effective cunning is partly responsible for her arrogance; she purposefully demeans herself so that others will let their guard down around her; in turn, this allows Trina to come off as innocent in spite of her snappy personality.
Trina shares Obake's disregard for the law and views villainy as freedom. Much like Hiro did in the past, Trina enjoyed the thrill of the bot-fighting ring and the easy money that came along with it. However, her penchant for thieving went against her mission regarding Hiro, showing that she is capable of diverting from her directive despite her inherent loyalty to her "father".
Trina is an adolescent girl, slightly taller than Hiro. In her human form, she has fair skin, back-length auburn hair, and light blue eyes, matching Obake's. She dresses in a purple beanie, a pink short-sleeved shirt, and grey ankle-length jeans. She also wears black, fingerless gloves.
In season two, she now has purple trimming and circuitry across her body. Her legs are thickened with two prongs at the base. Her arms both contain four claws and shoulder pads, but the right is a blue hefty left arm with a gray shoulder pad while the left is green and thin with a black shoulder pad. Trina's head controls the body, although it is encased in a glass dome and with a cut-down mohawk.
In the episode "Legacies", Trina's appearance is once again altered. No longer resembling a teenager, she now looks more like a young adult and sports a more feminine version of Obake's clothing. She wears a black dress suit and still sports her hair has a side shaved mohawk, but with a red streak, making her appearance closer to her creator's.
Role in the series
Trina first appears in "The Bot Fighter", where a string of bot-related crimes has plagued San Fransokyo. After discovering a connection between the bots being used in the crimes and the bot-fighting ring that he once participated in, Hiro goes undercover to Good Luck Alley to find information on the culprit (whom he believes to be Yama). While sleuthing, he sees Trina in the midst of a battle, which she loses. When Hiro tries to get into Yama's office, Trina stops him as she doesn't want Yama to cancel the fights due to Hiro's sudden arrival. When Hiro critiques Trina's bot, she ropes him into helping her improve it. The two begin to bond as they work together, with Trina noting that she's a self-taught fighter. She also claims to be such a fan of Hiro's that she researched his old fights as reference. When Trina asks why Hiro chose to quit, he simply contends that he's over bot-fighting. Trina nevertheless encourages him to continue if he enjoys it; this causes Hiro to steadily fall back into his old habits.
He eventually renters the ring as an official fighter and goes against Trina as his first opponent. Though she loses the fight, Trina compliments Hiro's skill and even gives him a kiss on the cheek. Meanwhile, Go Go, Honey Lemon, Wasabi, and Fred sneak into Yama's office and learn that he isn't behind the crimes. This leads Hiro to deduce that Trina is the true culprit.
When Hiro confronts Trina, she admits to being the mastermind behind the crimewave and chides Hiro for being against her. Hiro confesses that his brother got him out of bot-fighting and encourages Trina to turn her life around, too. As she doesn't believe in reformation, Trina instead pressures Hiro to join her side, only to be foiled by the arrival of Big Hero 6. Unfazed, Trina summons a powerful killer bot to do away with the heroes while she slips away. Hiro tries to stop her, but his teammates' need for help forces him to let Trina escape. Later, Trina regroups with Obake, who expresses contempt for her grand thefts. He demands to be shown something useful, to which she responds by relaying footage of Hiro confessing why he gave up bot-fighting. Though Obake shows animosity towards Hiro for refusing Trina's offer, he consoles his daughter and declares that it's time to move forward.
In "Countdown to Catastrophe", Hiro is forcefully taken to Obake's lair, where he briefly reunites with Trina. At the time, Trina's head was detached from her body, revealing to Hiro that she is a robot. After calmly greeting him, Trina teases Hiro for not being able to figure it out himself, declaring that it's "so pathetic, it's cute".
As revealed in "Internabout", Trina managed to survive the destruction of Obake's lair. She is stored in a crate and taken out of the bay and to an abandoned warehouse by Noodle Burger Boy. Rather than helping Trina reassemble herself, Noodle Burger Boy leaves the warehouse to return "home". Afterwards, Trina manages to reattach her head to her body (though it remains loose) and becomes determined to find Noodle Burger Boy, whom she sees as a little brother. Trina upgrades herself with a deadly mech suit and a new mohawk (as her initial hairdo "got in the way"). She tests out her new form on Big Hero 6, and later goes to the Noodle Burger factory, where she finds Hiro trying to remove Obake's chip from Noodle Burger Boy's system. Trina prevents Hiro from tampering with Obake's chip, but fails in her attempt to kill him. She and Noodle Burger Boy are nevertheless able to escape.
In the Season 2 finale "Legacies", Hiro finds Trina in her warehouse, and discovers the truth behind the Buddy Guardians. Trina blames him for Obake's apparent death and seeks to recreate Obake's dream of destroying San Fransokyo, but with the added twist of replacing humanity with robots, with herself as their leader. When Noodle Burger Boy is taken away, an enraged Trina fires at Hiro who is protected by Baymax, but knocks Baymax over and Hiro holds onto the ledge. Roddy Blair and Mini-Max then appear behind her in a colossal mech called Mega-Max, with Roddy controlling the mech's arms to grab Trina and toss her into the city, thereby severing her connection with the conductors. Trina's plans are ultimately foiled when her talk about Obake's legacy inspires Hiro to keep Tadashi's legacy alive instead and mass-produce Baymax's healthcare chip and, with the help of neurotransmitter controlled army of Megabots, replace the copies of Obake's chip in the Buddy Guardians so they behave like Baymax and help people. She tries to attack Hiro but Hiro throws Mini Magnets at her and entangles her in the lashes, ending her robot rebellion and keeping Obake's legacy alive instead.
- Trina shares the same eye color with Obake, hinting at their ties.
- Throughout "The Bot Fighter", she only addresses Hiro by his last name. She calls him "Hiro" for the first time in "Countdown to Catastrophe".
- Trina is the second character Christy Carlson Romano voices in a series created by Mark McCorkle and Bob Schooley, who were the creative team behind Kim Possible, where Christy Carlson Romano played the leading role.
- In her original form, Trina's short-sleeved shirt seems to be a homage to the midriff outfits Kim Possible wore, as both characters were voiced by Christy Carlson Romano.