Xíng Hài, a necromancy-wielding demon exiled in the human realm after the War of the Fading Dusk severed ties to her homeland, harbors centuries-simmering resentment toward humanity, sharpened by her adversarial history with Lǐn Xuě Yā. Mastery over corpse manipulation, qi channeling, and the Diào Mìng Jí technique—which weaponizes dark energy—fuels her role as a cunning antagonist, deploying undead legions to destabilize foes and orchestrate strategic strikes.

The prequel *Thunderbolt Fantasy Gaiden* delves into her origins alongside Lǐn Xuě Yā and Shā Wú Shēng, unveiling her manipulative cunning and tangled alliances forged to undermine human rivals. Her schemes interlace with wars over mystical artifacts like the Tiān Xíng Jiàn and Mó Jiàn Mù Lù, as she exploits supernatural weapons to fracture human factions, often colliding with protagonists’ efforts to thwart her ambitions.

While her specific role in *Thunderbolt Fantasy: Tōriken Yūki 4* remains undisclosed, her enduring presence across prior narratives suggests continued influence through necromantic machinations and vengeful grudges, perpetuating her shadow over the series’ unfolding conflicts.