BackBiter is a magic short sword made out of a black metal - even it's edge is black. It's edge is keen, however, and imbues a +1 adjustment to the blade's damage in combat (no adjustment "to hit"). The blade's special enhancement comes into play when the PC's opponent exposes their back to him. At this point, the player may opt to attempt a backstab (+4 hit, x2 damage). If successful, the blade may not be used again to attempt a backstab for a full 24 hrs. If unsuccessful, further attempt may be made when the opportunity presents itself, up to and until a successful backstab attempt is made.
In the hands of a thief, Backbiter adds to the damage multiplier for one successful attempt per day. So, if the thief currently has a X2 backstab multiplier, he can attempt to use Backbiter for a X3 backstab multiplier until he succeeds, at which point he'd have to wait 24 hrs to attempt a X3 backstab (obviously he'd still be able to backstab for X2).
As a side effect of the black metal, a thief can hide in shadows with Backbiter in hand without fear that light may reflect off of the blade.
There is more than one Backbiter in existence. There have been at least two daggers made to the exacting magical specifications and one long sword is rumored to exist.
Tenkar's Tavern is supported by various affiliate programs, including Amazon, RPGNow, and Humble Bundleas well asPatreon. Your patronage is appreciated and helps keep the lights on and the taps flowing - Your Humble Bartender, Tenkar
Tenkar's Tavern Discord Server Events - link - https://discord.gg/fReGmuD - Click to embiggen