Demon Slayer

Demon Slayer is Meng Chuan's signature saber, an ancient divine armament that grows by devouring flesh, blood, sin, and baneful aura. Its previous wielders used it in human massacres and sometimes fell under its influence; Meng Chuan chooses it despite that history, renames it, and redirects its appetite toward demons. Long cultivation beside him eventually makes it more compatible with his physical combat than treasures of a formally higher grade.

History

Choosing an evil saber for a different purpose

When Meng Chuan completes his training on Archean Mountain, his Saber Soul attracts three Heaven-level divine armaments. The blood-red saber is the strongest and fastest-growing option, but its surviving memories show owners becoming slaves to its urge to kill. Meng Chuan's Saber Soul suppresses its weakened baneful influence, and the weapon's dossier says its worst historical state required a third-level Essence Soul to control. He accepts the risk on the condition that his will remain stronger, renaming the saber Demon Slayer so that its future growth will come from killing humanity's enemies rather than feeding on humans. (Chapters 129–130)

At first, Demon Slayer functions mainly as an exceptionally sharp conduit for Meng Chuan's own saber arts. It begins feeding again after he leaves the mountain, devouring powerful demon monarch bodies and the resentment attached to them. Fu Jiao's unusually potent lifeblood produces a marked increase in sharpness and destructive force, while a Creation-realm alien corpse supplied by Qin Wu later restores much of the divine armament's lost grade. These upgrades are not free power detached from the wielder: every increase also strengthens the evil pressure Meng Chuan must keep under control with his Essence Soul and will. (Chapters 156, 198–213, and 278–279)

A weapon cultivated through the outer realm

Meng Chuan continues nurturing Demon Slayer with his Quintessential Essence and the laws behind Infinite Saber. It grows with him from an Imperial Lord-level weapon into a Fifth Tribulation treasure, and devouring part of an Eight-Headed Star Swallowing Snake's corpse further strengthens its physical foundation. Its long companionship makes it unusually responsive in his hands; although the Bloodblade Disc is his intrinsic treasure, he judges Demon Slayer more compatible for close combat and able to exceed ordinary Sixth Tribulation weapons when carrying his saber laws. (Chapters 525, 555, and 566)

A wine-cup shard taken from a plundering faction triggers another transformation. The shard releases baneful aura dangerous even to Fifth Tribulation Eminences, which Demon Slayer absorbs over nineteen days until it becomes dark red and can carry the aura into its strikes. That property disrupts Cave Lord Scenic Cloud's consciousness but cannot overcome the serpent's regeneration by itself, so Meng Chuan combines it with physical strength, saber technique, Essence Soul attacks, and an array. He later leaves the saber behind before a ruin expedition rather than risk losing it, then resumes carrying and cultivating it; by the latest account it has reached the Sixth Tribulation level and can absorb only those forbidden-creature Life Core fragments whose nature is compatible baneful aura. (Chapters 579–584, 591, 649, 657–658, and 692)

Abilities and properties

Growth through devouring

Demon Slayer can consume sufficiently potent flesh, blood, sinful aura, resentment, and certain baneful auras. A drained corpse can disintegrate into dust, while stronger meals take longer to absorb and digest. Feeding restores the weapon's faded spirituality and grade, and compatible law nurturing lets it advance with Meng Chuan. It is selective rather than universally voracious: early lesser demon corpses do not interest it, and among forbidden-creature Life Cores it can use baneful-aura fragments but not every other type. (Chapters 130, 156, 213, 279, 555, 580–581, 649, and 692)

The same appetite is a hazard. As the saber becomes stronger, its baneful pressure can invade or influence its owner, and earlier wielders lost control to it. Meng Chuan suppresses the weakened saber with Saber Soul and later with increasingly powerful Essence Souls; he explicitly intends to stop feeding or replace it if his control approaches its limit. This makes compatibility and mental strength operational requirements, not merely moral safeguards. (Chapter 130)

Saber effects and interactions

The saber is exceptionally sharp and carries Meng Chuan's own Quintessential Essence, physical power, and saber laws into close-range attacks. Early on, it can release broad saber beams suitable for groups, but Meng Chuan notes that dispersed ranged force drains Quintessential Essence quickly and lacks the concentration needed against a powerful single enemy. Its mature strength likewise depends on his technique: the weapon supplies material, accumulated power, and baneful properties, while Infinite Saber and later Tribulation laws determine the attack's actual form and scale. (Chapters 130, 133, 213, 525, and 555)

After the wine-cup shard transformation, contact injects baneful aura that interferes with a target's consciousness and ability to execute complex moves. Cave Lord Scenic Cloud remains able to counterattack and rapidly heal the saber wounds, proving that mental disruption does not guarantee bodily defeat. Demon Slayer also absorbs ordinary resentment and sin around Meng Chuan but does not reveal or remove a karmic blood curse attached through those killings. Its appetite is therefore not a general defense against every curse or spiritual effect. (Chapters 376 and 580–584)

Owners and wielders

Relationships

• Meng Chuan: His will prevents the saber's appetite from defining its use, while his cultivation turns its capacity for growth into a weapon against demons and outer-realm enemies.
• Bloodblade Disc: The disc remains Meng Chuan's intrinsically refined movement and defensive treasure; Demon Slayer becomes the more compatible close-combat weapon after growing with him since his early Godfiend career.