Lilpilin serves as a dark knight in the Dark Territory of Underworld, holding the eleventh rank under commander Vixur Ul Shasta. Born after a peace treaty was established in the Dark Territory, she avoided childhood enslavement despite her small stature. Departing from the typical path of human women joining the dark arts guild after preparatory school, she instead attended cadet school to train as a dark knight. There, she discovered a late-blooming talent for swordsmanship, ultimately achieving one of the highest positions possible for a human female within the Dark Territory's military. Following her knighthood, she managed an institution similar to a nursery, caring for infants abandoned by parents from remote areas where slave trafficking persisted.

She possesses blonde hair reaching her shoulders and yellow eyes. Her facial features include high cheekbones described as reminiscent of Northern European nobility, contrasting with her darker skin tone. On duty, she wears jet-black full body armor marked by numerous scratches but meticulously maintained through regular polishing.

Lilpilin privately questioned the Dark Territory's societal rule based solely on strength and plunder, though she initially lacked the articulation to express these doubts. Her perspective shifted after working under Shasta, whose ideals of peace she came to support wholeheartedly. This loyalty drove her to independently attempt the assassination of Emperor Vecta when his reappearance threatened Shasta's peace plans between the Dark Territory and Human Empire. Disguised as an attendant, she infiltrated Vecta's quarters with a concealed knife but failed when he intercepted her attack. Despite interrogation and physical restraint, she refused to divulge information about superiors or collaborators. Her resolve remained unbroken even under duress, and she met her end through a fatal neck fracture inflicted by Vecta.