Norman's sword suddenly became heavy and heavier, which made Allen immediately step back. Surprisingly, as Norman's sword became heavier, his grip weakened, which gave Allen a chance to retreat but raised a big question: why did the sword become heavy while his grip was weakened? But before Allen could think about the possibilities, his stomach was pierced by Norman's suddenly extended sword.
'Pervenire Mors is a sword made from the monsters of Old Cato in the 8th-floor dungeon. They use their nails which can extend and retract, to catch their prey from afar. Its power wasn't the best, but it could be deadly depending on how you use it.'
Just as Norman thought, Allen's stomach was successfully pierced by his armacar but not through the back. This was because Pervenire Mors did not have enough strength to penetrate Allen's body, and Norman didn't use enough strength to push his sword forward in a surprise attack.