While Wolverine's adamantium-coated claws are the stuff of legend, his son Daken actually one-upped Logan by coating his own claws in a metal that wasn't just sharper, but was even able to defeat his father's vaunted healing factor.
In one of the great tragedies of his life, Wolverine accidentally abandoned his son Akihiro after the murder of his wife Itsu by the Winter Soldier. Not knowing that his unborn son would possess his healing, Logan believed the child dead, when in fact Daken was taken and raised by the villainous Romulus to kill and potentially replace his father. A lifetime of disrespect — including the canine nickname 'Daken' — instilled an immense hatred within Wolverine's son, motivating him to attempt to best his father in every way possible.
Related: Marvel Ruined Wolverine's Adamantium Bones with One Cheap Weakness
To that end, Daken sought out the fabled Muramasa blade, first seen in Daniel Way and Javier Saltares' Wolverine #40. The sword was created by the immortal swordsman Muramasa, who forged it from Logan's rage, creating a blood-red sword that slices down to the molecular level. Due to the physics-bending level on which it cuts, the Muramasa blade vastly slows healing, and has been touted as the one weapon that could actually kill Wolverine despite his powers (and indeed was used to kill a clone of Sabretooth.) With cutting-power even adamantium can't beat (and the ability to cut energy itself), the blade became Daken's prize, and Wolverine's son was eventually able to acquire a shard of the Muramasa blade, which he had bonded to the two claws that emerge from his wrists in a procedure darkly similar to Logan's experiences with Weapon X.
Thankfully, Logan was eventually able to defeat his son,
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