Leysritt functions as a caretaker and maid for the Einzbern household in Fuyuki City. She and her fellow homunculus Sella were dispatched from the Einzbern family to oversee Illyasviel von Einzbern and Shirou Emiya during Irisviel and Kiritsugu's overseas travels.

Physically, she possesses short pale hair, red eyes, and a tall, well-endowed figure. Her typical attire is casual—a shirt, shorts, and a necklace—instead of a traditional maid uniform. Her eyes are sometimes depicted with less shine or dullness, reflecting her lethargic nature.

Personality-wise, Leysritt exhibits a relaxed, lazy demeanor. She frequently watches television and avoids household chores, leaving duties to Sella and Shirou. Her speech is direct and unfiltered, occasionally featuring deadpan snarking or teasing, particularly aimed at Sella. Despite her laziness, she fulfills responsibilities when necessary, such as caring for others during illnesses. She prefers the nickname "Liz" from those close to her.

Her combat capabilities include high physical strength and proficiency in hand-to-hand combat and halberd techniques, demonstrated during training sessions with Sella. While her full combat potential remains largely unexplored within the narrative and she avoids major battles, she and Sella occasionally employ magic for mundane tasks like drying laundry or heating food.

She shares a sisterly bond with Sella, forming a "Sibling Yin-Yang" pairing; Sella's strictness and responsibility contrast with Leysritt's laid-back attitude. This leads to tensions over household management, though they cooperate when needed. Her relationship with Illya is affectionate, including occasionally watching magical girl anime together. She interacts neutrally with Shirou, despite Sella's frequent frustrations with him.

In spin-offs like *Carnival Phantasm*, she appears briefly in comedic scenarios, such as following Berserker on an errand. In *Capsule Servant*, she accompanies Illya (disguised as "Celebloomers") and displays knowledge of Japanese culture.