Lucrecia Otis is a female recovery mage and a member of the S-rank party known as First Unit, which serves under the adventurers guild Silver Rabbit of the Night Sky. She is recognized as an S-rank healer within the top clans elite first unit and is often referred to by the nickname Luke. Her appearance is that of a slender young woman with golden hair and emerald-green eyes, and she carries a gentle demeanor that belies her formidable capabilities.

By upbringing or inclination, Lucrecia initially relied on natural talent and instinct when casting healing magic. However, after losing comrades in the field, she underwent a significant transformation and shifted toward a theory-driven approach to magic, studying and understanding the principles behind her spells rather than relying solely on intuition. This development allowed her to grow into a versatile mage capable of creating original spells and supporting her party at a level comparable to other S-rank explorers. Her personal motivation stems from a desire to protect her companions and to ensure that her skills are reliable enough to prevent further losses, making her both a diligent student of magic and a dependable ally in dangerous situations.

In terms of notable abilities, Lucrecia possesses a rare sensory-type supernatural power that enables her to trace the remnants of magic. By analyzing the residual mana left behind after a spell has been cast, she can determine where the magic was used and who invoked it. This magic-tracking ability is unique among healers and provides critical reconnaissance and intelligence-gathering advantages during expeditions. She balances her recovery magic with offensive and support spells, ensuring that her squad maintains both endurance and combat momentum. Despite her slim build, her healing abilities rival those of other S-rank explorers, and she is described as a mood-maker within her party, contributing to group morale and cohesion.

Her role in the story is that of a supporting healer and tracker within the First Unit, a top-tier party that undertakes high-risk dungeon explorations. Her key relationships are with her fellow party members in the guild, though specific interpersonal dynamics are primarily defined by her position as both a caretaker of their health and a source of positive energy. Throughout the narrative, her development is marked by the shift from instinct-based casting to a more analytical and versatile magical repertoire, a change driven by the trauma of past losses and her commitment to becoming a more effective protector.