Sal Lassiter was a shapeshifter, and brother to David and Margo Lassiter. Sal was also the vice president of Trinty Plasma Blood Management Solutions, having held a position on the board of directors since April 2010. Before his death, it was thought that he would become the successor to the family once his father passed.
Sal and his bodyguard Marv, a wraith arrive at the upscale restaurant Il Secundo. His arrival interrupts Ennis Ross' conversation with the matre d' Maurice, who turns his attention to Sal. Maurice leads Sal and Marv into the private room in the back of the restaurant. Once he enters the club Sal runs his hands through his hair and his hair changes from brown to blond, and crosses the room filled with various other monsters to the bar. He is then approached by Julian Duval who tells him to leave the club, when Sal refuses Julian punches Sal, they tussle with each other, and as Sal gets the upper hand Julian starts to turn into a werewolf, and they are quickly separated. As Julian leaves the bar, the lights suddenly go out and a clawed hooded figure appears and begins slashing at any monsters that get in his way, including Marv and Sal.
Sal is able to escape the club, however he is severely wounded in the process. He makes it outside to a ferry landing were Ennis is about to propose to his girlfriend, as he lies in Ennis' arms, he tells Ennis "David... I'm sorry. I didn't have a choice." When suddenly the hooded figure appears, first violently slamming Tamara into a rolling steel door, before he approaches Sal and rips out his heart.
It is later revealed in a flashback that he stopped Violet Duval from running away with David. This is what is was sorry about.
From what is seen of him, Sal is loyal to his kind and his family. Sal even went as far as to forbid Violet to see his brother David, fearing for his safety. As he began to die, he wished to say sorry to his brother for what he had done, wanting him to know that he had his best interests at heart.