Laethreel, born Shuraku, is the hybrid daughter of a demon father and human mother. Her dual lineage bestows unique abilities, most notably the "entrancing eyes" inherited from her father—a power to bewitch humans and demons alike, sparking relentless conflict. Denying her demonic roots, she reinvents herself as a demon hunter, adopting the name Laethreel and wielding Grenki, a sentient, bloodthirsty sword that selects her as its master. This bond empowers her to battle supernatural threats without a traditional protector. Her mission to rescue Princess Shurain of Gandia from the demon noble Aju intertwines with unresolved familial strife.

Her younger brother, Leedyle, now the demon lord Ranka, covets her entrancing eyes as a source of power, fueling a rivalry that escalates into existential threats. Laethreel’s internal turmoil stems from her struggle to suppress latent demonic traits while clinging to a human identity.

Guided by her foster mother, Lady Manthrum, queen of Gandia, and accompanied by the enigmatic demon Anshu—whose true allegiance remains uncertain—Laethreel navigates precarious alliances. These relationships underscore her vulnerability and resolve to carve an identity beyond her heritage.

Spanning 40 light novels, her journey centers on self-definition amid external peril. The OVA adaptation narrows its focus to her initial mission and familial clashes, leaving wider narrative arcs confined to literary form. No additional portrayals in spin-offs or extended media are documented.