Tyrfing

Info
A seemingly useless weapon, the Tyrfing gains in damage the lower the user's health percentage, but it's slow speed means other, faster weapons will likely deal more damage over time, with a lower chance of being killed at the same time.

Trivia

 * In previous versions of the game, Tyrfing purportedly carried special effects against the Dungeon Guardian.
 * Tyrfing is possibly a reference to the magic sword Tyrfing in Norse mythology or a one-handed Dark elemental sword in Castlevania
 * The effect of gaining damage the lower the user's health becomes may be a reference to evil swords, in general, in mythology, as 'evil' weapons are said to 'steal the user's souls' as payment for their immense strength.
 * In NT6, Tyrfing has a tooltip: "Legendary accursed sword. Grows stronger according to how near death you are."