I just finished rereading the whole thing on Dreame last week, and honestly, the title is a bit of a misdirection if you ask me.
The main character is definitely a woman named Pell. The story starts with her being sold into slavery in a vampire-run society to pay off her family's debts. She's the one we follow, the 'pet' in the title, given to the infamous vampire noble Damien Vade. The entire narrative is from her perspective, experiencing the world's cruelty, the politics, and Damien's complex behavior through her eyes.
That said, the story is a dual-lead narrative in spirit. Damien Vade is just as central. He's not a traditional love interest; he's cruel, unpredictable, and possessive, but his character has massive depth that unfolds slowly. The plot is as much about Pell surviving and adapting as it is about unraveling the mysteries surrounding Damien—his past, his power, and his strange fascination with her. Calling Pell the sole protagonist feels incomplete because the story's tension and evolution hinge entirely on their twisted, evolving dynamic. Without him, there's no story; without her, we have no emotional anchor.