 Ogg felt Trevor's characterisation had evolved over time. He said, "Nuances and character traits that began to appear — his walk, his manner of speech, his reactions, definitely informed his development throughout the game". Ogg cites Tom Hardy's depiction of English criminal Charles Bronson in the 2008 biopic Bronson as a strong stylistic influence on his portrayal of Trevor. Ogg opined that while Trevor embodies the violent, psychopathic Grand Theft Auto anti-hero archetype, he wanted players to sympathise with Trevor's story. "To elicit other emotions was tough, and it was the biggest challenge and it's something that meant a lot to me", Ogg explained. Fonteno felt that growing up in South Los Angeles and being exposed to gang culture helped him connect to the character of Franklin. He drew upon his earlier involvement with a gang and trafficking drugs in his portrayal of Franklin. "I lived his life before ... He's been surrounded by drugs, the crime, living with his aunt — I lived with my grandmother — so there was a lot of familiarity", Fonteno said. Having not worked as an actor since portraying Face in the 2001 film The Wash, Fonteno sought counsel from Luke and Ogg to refine his acting skills.
