Whne found, this blade appears as a rusty, dull, and pitted longsword. It has a hilt wrapped in a tarnished silver wire and a pommel set with what appears to be a purple glass jewel. It will radiate a faint magical dweomer if examined with detect magic.
When used in battle, however, the blade will gradually awaken. After each use, the blade becomes sharper, cleaner, and more valuable. If specific monsters are slain, its power will increase.
Until the first listed monster is defeated, it grants no bonus to hit or damage, but will penetrate a DR of +1. When the following evil monsters are slain using the sword, the respective powers are activated:
Undead of less than or equal to CR 4: The sword becomes +1 to hit and damage
Undead of greater than CR 4: The critical threat range of the sword becomes 18-20.
Evil outsider: The sword develops the power to cast cure moderate wounds on its wielder once per day.
Evil magical beast: The sword develops the power to cast bull's strength on its wielder once per day.
Evil giant: The sword becomes +2 to hit and damage.
If the sword is ever used to kill a good creature, all powers are lost and the cycle must start again. The powers will not function for evil creatures.
I have checks by 1, 4, and 5 so I guess those were the powers Bix managed to activate.