Lizzie Garland serves as the personal bodyguard and childhood friend of Claudia McCunnen, a high-ranking figure within the criminal organization Inferno. She commands the organization's shock troops during missions such as arms shipments and other operations. Lizzie is a tall woman with a cool and somewhat aggressive demeanor, but beneath that exterior she is surprisingly affectionate and fiercely loyal. She is an excellent markswoman, though her skill does not match that of individuals who bear the title of Phantom. She is initially reluctant to trust those outside her inner circle until they prove themselves to her.

After the climax of episode 10, Zwei becomes the new Phantom and Lizzie is assigned as his partner during field operations. Over time she grows fond of Zwei and assists him when he retrieves Cal Devens from a rival gang's territory. Later, when Zwei flees Inferno, Lizzie is reassigned as the partner of the next Phantom, Drei, who is Cal Devens. Despite wanting to honor Zwei's wish to keep Cal from being trained as an assassin, Lizzie finds herself unable to prevent Cal from continuing to work for Inferno as a way to pursue revenge against Zwei. When Cal kidnaps Mio in Japan, Lizzie attempts to stop her. During the confrontation, the two play a game of Russian roulette using a pocket watch; Lizzie hesitates to pull the trigger on someone who has become close to both her and Zwei, and she is shot and killed by Cal.

Throughout the story, Lizzie's motivations are rooted in her loyalty to Claudia and her growing attachment to Zwei. After Claudia's death, she has no reason to remain with Inferno and privately wishes to leave the criminal life behind. Her development shows a progression from a hardened, suspicious operative to someone capable of genuine emotional bonds, though these ultimately lead to her downfall.