Vorpal Sword

The Vorpal Sword was a highly powerful magical artifact that appeared in the cave of Lamashtu. It was wielded by the monk Yotokono Kusetare during his time in Quata, and was instrumental in the demise of the Spawn of Kalderus. It had the magical propery of being able to sever heads with nearly no effort, and was the only weapon powerful enough to stop the jabberwock. It was returned to its original dimension as part of the bargain to return the being called "Hunter" back to his home.
ヴォーパル +5 (Katana)
Aura strong necromancy and transmutation; Masterwork; 6 lbs;
Damage 1d8 + 5; Critical 18–20/×2; Type S
This sword has a single-edged blade so slender that it appears transparent near the end but it is nevertheless immensely strong and durable. The guard has an organic shape and glows dimly. The grip is fitted to the shape of the wielder’s hand and comfortably accommodates two hands. The blade is engraved with strange letters: ヴォーパル. The weapon is distinctive due to its astral glimmer.
Katana: Characters can use this weapon two-handed as a martial weapon, but must take the Exotic Weapon Proficiency (katana) feat to use it one-handed.
Vorpal: This potent and feared ability allows the weapon to sever the heads of those it strikes. Upon a roll of natural 20 (followed by a successful roll to confirm the critical hit), the weapon severs the opponent's head (if it has one) from its body. Some creatures, such as many aberrations and all oozes, have no heads. Others, such as golems and undead creatures other than vampires, are not affected by the loss of their heads. Most other creatures, however, die when their heads are cut off. 
Deadly: When you use this weapon to deliver a coup de grace, it gains a +4 bonus to damage when calculating the DC of the Fortitude saving throw to see whether the target of the coup de grace dies from the attack. The bonus is not added to the actual damage of the coup de grace attack.
Chosen Wielder: This weapon chooses its wielder for life. If you relinquish your grip on it for 2 or more consecutive rounds, it automatically opens a tiny portal and returns to the strange place it originated. It can be resummoned into your hand as a swift action.
Category:Magical Artifacts