GTA 6's Lucia was the main focus of the first trailer and received various scenes in the recently released trailer 2. While Jason Duval, the male protagonist, took the major screentime in the second trailer, fans got various glimpses into the life of the female protagonist and what role she might play in the story.
This article breaks down the second trailer and discusses everything that was revealed about GTA 6's Lucia.
Everything we got to know about GTA 6's Lucia from trailer 2

The second trailer quickly revealed the full name of the female protagonist. GTA 6's Lucia Camino will take the lead alongside her love interest, Jason Duval, in Vice City, as they both embark on various adventures. While the trailer started with Jason, we quickly see him visiting the Leonida Penitentiary to receive Lucia.
This could confirm the theory that GTA 6's Lucia might be in prison at the beginning of the game, as players will get to complete missions as Jason. Further, it showcased that she is a fighter, as we see her in a ring brawling with someone. The scenario resembled an MMA-style bout, further hinting that Lucia could be the brawn of the duo.

The second trailer also further built on the plot and showed both Lucia Camino and Jason Duval deeply in love. Rockstar Games also revealed that Lucia has been taught to fight by her father from a young age. However, she fervently wishes to have a good and happy life with Jason in Vice City.
This could be a major plot point since the developer also revealed that the protagonists are in the middle of a huge controversy. One of the scenes showed them talking about "doing something right", implying it could be a big job. Apart from everything else, the second trailer delved into the character of GTA 6's Lucia and showcased her relationship with Jason.

On top of that, there were various scenes of her in action, cementing the fact that she will not just be a "second lead" but will heavily feature in anything and everything dangerous. It is also worth noting that Lucia was shown in a bright vest, which might hint at players needing to complete some community service minigames.
This could be directly tied to her being imprisoned and having to perform these actions as part of her parole.
Also check: Which consoles will GTA 6 be on