L.A. is an artificial being created by Douglas Rosenberg for Project Leviathan, alongside Ellis. He lacks Ellis's supernatural witch-like abilities but possesses enhanced physical attributes granting superhuman agility and strength. His primary weapon is a monofilament wire, capable of cutting through stone and human bodies with deadly precision.

He nurses a burning hatred toward humanity, particularly targeting his creator, Rosenberg. This contrasts sharply with his obsessive infatuation for Ellis, whom he ceaselessly watches and strives to protect, despite her initial lack of reciprocation. This fixation compels him to intervene on her behalf, defying orders and risking himself.

Initially tasked by Rosenberg to merely monitor Ellis and Nadie's journey without interference, L.A.'s actions escalate into boundary-crossing interventions, forcing Rosenberg to send Ricardo to capture and discipline him. After confinement, L.A. is released and resumes his surveillance of Ellis.

As one of the last survivors of five artificially engineered subjects infused with witch DNA, L.A. shares a connection to Ellis's origins. His emotional instability triggers violent outbursts, including killing individuals for minor provocations like a glance. Despite this volatility, he occasionally demonstrates a perverse loyalty to Ellis, such as secretly aiding her and Nadie during their travels. His interactions fleetingly reveal respect for formidable figures like Ricardo, though he generally deems himself and Ellis superior to humanity.

L.A.'s development sees his obsession intensify, culminating in acts like stealing a kiss from Ellis while she sleeps. His actions grow increasingly unpredictable, leading to direct defiance of Rosenberg's authority as he prioritizes his warped devotion to Ellis over the mission. His lack of humanity paradoxically fuels a single-minded, often destructive, pursuit of connection with Ellis, framing him as a tragic figure.