Progenitor Blade

The Progenitor Blade is Kai’s shape-changing weapon made from strands of Leo’s hair. Kai also calls it the needle and the Divine Needle, nicknames reflecting the small-looking source material and the disproportionate danger of a weapon capable of erasing divine beings. (Chapters 548, 555, 568–569)

History

Creation and first execution

Kai keeps strands of his progenitor father’s hair and fashions them into a blade during his confrontation with Aion. The weapon’s first demonstrated strike severs Aion’s head, revealing a means of bypassing defenses that ordinary divine arms cannot reliably overcome. Kai names it the Progenitor Blade and emphasizes that its strength comes from Leo’s nature, but he is the artifact’s maker and owner rather than merely a borrower of one of Leo’s possessions. (Chapter 548)

Training restriction

Kai brings the weapon into his training with Clarisse and refers to it casually as “the needle.” Leo intervenes and takes it away so Kai cannot use an erasing weapon to cheat the exercise or cause unacceptable harm. That removal is temporary safekeeping by the source of its material, not a transfer of title: Kai later again carries and displays the blade during his infiltration of Aion’s forces. (Chapters 555, 568–569)

War with Aion

Among disguised enemies, Kai presents the blade as capable of killing any god, including Leo, and uses its reputation and actual erasing force against supposed traitors. During the final battle he changes it from a sword into bandage-like gauntlets around his fists, judging that direct blows will connect more reliably than a conventional edge. Each landed punch then transmits the blade’s erasure into Aion and forces him backward despite his merged decay power. (Chapters 568–569, 576–577)

Abilities and properties

The blade carries a Progenitor-grade erasing effect. Rather than merely poisoning a target as ordinary contact with Progenitor Decay may do, it can erase what it cuts and threaten gods, primordials, and similar beings. Kai can reshape it without losing that property, turning the sword into close-fitting gauntlets that make even stray punches dangerous. Its limits are practical rather than quantified: Kai must still land an attack, Leo can confiscate it, and its power does not itself prevent Aion from continuing to fight after being struck. (Chapters 548, 555, 569, 576–577)

Ownership and custody