Every GTA main character is partially characterised by the city they reside in. Reading between the lines.
The pattern
Tommy Vercetti and his 1986 Vice City. CJ and the gang map of SA. Niko and his relationship with immigrant Liberty City. Michael, Trevor and Franklin, and a Los Santos made for each of them.
The hero character and the map are designed as a pair. Lucia and Jason will be characterised by Vice City and Leonida in similar ways.