Role in the series
In "Big Problem", a mutated Knox breaks into Frederickson Manor, attacking Fred and Mini-Max. He recites a peculiar line before taking his leave. He does the same with Alistair Krei at Krei Tech headquarters. Krei calls upon Big Hero 6 to stop this menace, promoting the team to investigate. Both the Fredericksons and Krei were scheduled to meet with Orso Knox, leading the team to search for a connection. They visit Knox's home, but he is nowhere to be found. Baymax scans for Knox, but the monster arrives and attacks. They are able to scare it away with Baymax's Overdrive Mode, allowing them to continue their investigations at Fred's manor. There, Honey Lemon deduces that the monster is indeed Knox, which Baymax confirms as the DNA of Knox and the monster are identical. Using Knox's planner, they see that he is attacking those of whom he had planned meetings with, leaving his final target to be Liv Amara. Knox attacks Amara at a gala event, but Karmi is able to sedate him using biotech. Knox is then taken into Amara's care at the Sycorax genetics lab.
Months after his incapacitation in "Prey Date", Hiro becomes suspicious of Liv's supposed "treatment" of Orso Knox. He coerces Karmi to assist in accessing Knox's containment unit. Knox manages to escape, taking Hiro with him. Furious, Liv orders Big Hero 6 to kill Knox, but before they can, Hiro realizes that Knox has never meant any harm and that any destruction that he's caused was out of sensory overload or hunger. Big Hero 6 spares Knox and returns him to Sycorax, where the team is able to "cure" him. Knox, once again human, makes a public statement regarding his health to save face for the company. In private, however, Liv forces Knox to remain an investor for her company by threatening to turn him back into a monster, using a chip that was implanted into his body, should he refuse.
- Knox's monster roars are those of a lion or tiger and the roars of the Tyrannosaurus Rex from the Jurassic Park films.