How does gta online expand on the story mode experience?

Grand Theft Auto Online extends the single-player story mode of Grand Theft Auto V by transforming its fictional world into a shared multiplayer environment. While the original story mode features three protagonists navigating a linear narrative, GTA Online shifts to a customizable silent protagonist controlled by individual players within the same open world of San Andreas. This allows exploration of Los Santos and surrounding areas with up to 30 players simultaneously, supporting both cooperative and competitive gameplay. The game retains the story mode's open-world design but introduces new multiplayer-centric activities like heists, races, and free-mode events, offering varied experiences beyond the original narrative. However, the evidence provided does not confirm whether story mode plotlines or characters are directly expanded in GTA Online, focusing instead on its multiplayer infrastructure and world-sharing capabilities.