Louis' star had hardly begun to rise when he was brutally cast into his current state. A talented Jazz musician with a lack of self-control and an unhealthy appetite for other young men, his sexual inclination almost got him killed on several occasions. It was only when he had the poor luck to receive the patronage of Marie Laveau, who had an interest in the scene from her time as mistress of Storyville. She saw to it that he got the exposure he needed and didn't get it where he didn't, but the situation was quickly ended by Ange Poncelet, who Embraced him one night out of a mixture of obessesive desire, jealousy, and spite.
Fleeing his sire, he went to the only one who he thought might be able to protect him, his dark patron. Marie took him in and taught him the truth of his ways, building on the background of voodoo he came from which had been one of the reasons she noticed him. However, when she tried to use his sexuality to lure him into a blood bond with her sire, he fled again, noticing the strange effect the blood was having on him. By himself, he tried to make sense of what had happened to him, torn by the understanding of his Catholic background, which would deem him damned, and that of the voodoo, which took a more enlightened approach. In time, he made his way back to his sire and attempted to learn what he could from her.
Her instability and deteriorating sanity touched something in him and his empathy increased when he began to piece together the full story of her life and unlife and the circumstances of their shared existence in New Orleans. He tried to keep her from associating too much with the priscus and her brood but was unable to intervene fast enough. He watched the rate of Ange's decline increase sharply as her new perspective encouraged her in the vices in which she'd learned to take refuge. He redoubled his efforts and has been trying to bring her out of her tailspin ever since. While he dislikes the rest of his current pack intensely, he won't abandon Ange.
In an odd way, taking care of Ange is how Louis has made sense of his new existence. While he couldn't put it to words, looking after her has given his unlife meaning and purpose. His loyalty to her, despite his initial hatred, is based on the oldest tie in the world: blood. She is the closest thing he has to family, thus he can't give up on her or abandon her to her own devices.
Louis has lost a lot of his youthful flamboyance and is a very reserved man now, prone to a melancholic air and a tendency to keep to himself when he isn't with his sire. He still pursues his music and is a fantastic saxophonist, but he rarely shares it with anyone, as if it were a personal possession from his lost mortal life that he keeps close to his heart and indulges in privately when he's missing it.
Louis is, as noted, dedicated to his sire. He dislikes the other members of the pack and, to be fair, most other kindred. He's still on terms with Marie, whom he's mostly forgiven for her earlier manipulations and whom he's hoping will help him save Ange. He also has taken to socializing with the Brujah since the war ended. As the most human of the vampires in the city, he finds them easier to relate to, particularly Golda, who has been trying to convince him to join their pack.