Bone Chilling Flame

The Bone Chilling Flame is Yao Lao's dense-white Heavenly Flame, distinguished by an icy sensation surrounding intense heat. It supports his alchemy, protects Xiao Yan in hostile environments, and anchors their connection while Yao Lao is imprisoned. After Yao Lao receives a new body and advances to Ban Sheng, he removes his spiritual imprint and transfers the flame to Xiao Yan, who gradually gains acceptance before refining it. (Chapters 63–64, 199–261, 699–730, and 1285–1295)

History

Yao Lao's signature flame

Yao Lao explains that he waited eight years in a lightless place for the rare conjunction of extreme cold and extreme Yin associated with the flame's appearance. Even after extensive preparation, assimilating it nearly burns him to ashes. He later manifests it from his soul form to refine Xiao Yan's early medicines, demonstrating precise temperature control as he calcines ingredients, separates impurities, and sustains a medicinal mixture without destroying it. (Chapters 63–64)

The flame's dual sensation is evident from its first use: it burns ingredients rapidly while the surrounding air grows colder. Yao Lao treats the combination as a Heavenly Flame's natural property rather than ordinary ice Dou Qi. He also states that it improves pill refinement and provides an advantage against opponents at a similar level, although the exact magnitude depends on the wielder rather than the flame alone. (Chapters 63–64 and 152)

Protection, instruction, and a seal of survival

While searching the underground magma crypt in the Tager Desert, Yao Lao wraps Xiao Yan in the Bone Chilling Flame. The white layer consumes magma splashes and isolates the external heat so thoroughly that Xiao Yan feels cold, but maintaining it drains Yao Lao's Spiritual Strength and imposes a strict time limit on the expedition. Yao Lao later uses the flame while helping Xiao Yan secure and refine the Green Lotus Core Flame, both shielding the cave and countering eruptions that would otherwise incinerate the surroundings. (Chapters 199, 214, 226, 228–229, and 238)

When Yao Lao is captured, he seals the essence body of the Bone Chilling Flame inside Xiao Yan through a white fire seal. The seal lets Xiao Yan confirm that Yao Lao remains alive and gives him controlled access to the flame and to Yao Lao's black ring. It is temporary entrusted control: Yao Lao's long-established connection remains, and Xiao Yan has not yet swallowed the flame through the Flame Mantra. (Chapters 699 and 730)

Deliberate transfer to Xiao Yan

After his revival and advancement to Ban Sheng, Yao Lao decides that Xiao Yan's Flame Mantra will benefit more from the flame than he will. Xiao Yan initially refuses because a Heavenly Flame remains valuable to Yao Lao as an alchemist, but Yao Lao removes his own spiritual imprint despite the strain and sends the resistant flame seed to his disciple. He instructs Xiao Yan to plant a new imprint, keep it at his brow, and wait rather than immediately force a merger. (Chapter 1285)

The remaining resistance fades faster than expected because the flame had already spent years sealed within Xiao Yan and had accepted his secondary control. Xiao Yan repeatedly blends his Spiritual Strength into it during travel until the white fire seal disappears and the flame responds as his own. He then refines it through the Flame Mantra and later counts it among the genuine Heavenly Flames in his combined arsenal. (Chapters 1287–1295 and 1497)

Abilities and properties

• Cold exterior and extreme heat: The flame appears dense white and produces an icy sensation around itself even while its inner heat calcines ingredients or blocks magma. The opposing qualities coexist; the corpus does not describe it as switching between separate ice and fire modes. (Chapters 63–64, 199, and 1287)
• Alchemy: Yao Lao uses it to purify ingredients, remove impurities, merge medicinal liquids, and warm completed pills under fine temperature control. These results combine the Heavenly Flame's heat with Yao Lao's own alchemical skill. (Chapters 63–64, 152, 257, 539, and 541)
• Environmental protection: A coating of the flame can isolate Xiao Yan from magma and other high-temperature environments. The protection consumes Yao Lao's limited Spiritual Strength while he is in soul form, so its duration is constrained by the user maintaining it. (Chapters 199, 214, 226, and 228–229)
• Combat and containment: The flame can envelop, block, and burn hostile forces, and Yao Lao uses it in both direct clashes and protection. It is powerful but not costless; spiritual-form use places greater strain on him than use from a restored body. (Chapters 238, 261, 539, and 699)
• Spiritual imprint and fire seal: A wielder can establish a spiritual imprint, and Yao Lao can remove his own imprint to enable transfer. The white seal at Xiao Yan's brow stores the flame essence and serves as a sign of Yao Lao's survival while the two remain linked. Residual resistance means removal of one imprint does not produce instant mastery by another person. (Chapters 699, 730, 1285, and 1287–1295)
• Multi-flame use: After refinement, Xiao Yan uses the Bone Chilling Flame as one component of techniques requiring several genuine Heavenly Flames. This compatibility results from the Flame Mantra and Xiao Yan's control, not from an independently demonstrated ability of the Bone Chilling Flame to merge with arbitrary flames. (Chapter 1497)

Ownership and custody