Haven Du'keir uses this weapon as he fights to learn his family's past.
Haven is a half-drow that was sentenced to be killed upon birth by Lloth.  When he and his twin were born, Lloth saw their beuaty and wanted to use them to recruit more followers.  Eilistraee took the twins and sent them far away so Lloth couldn't harm them.  Lloth found the twins and gave them each a gift.  She herself made the fang and put in it powers so that one day Haven might become powerful enough to fight for her dominion.
 
*Although Haven has mastered  the weapon's physical attacks, he is still unaware of its magical abilities.

Abilities
The magical swiftness of the fang allows bearer three attacks per two rounds.

Damage of 2d6 + *save vs. poison -3 on humans, dwarves and gnomes.

*Able to cast Web once per day.

*Spell Poison is memorized after bearer reaches 9th level

*Once bearer reaches 12th level, s/he is able to morph into animal at will

Defensive
*Raises bearers Hide/Move silently/Listen +2

*Able to cast Scrying once per day.

*Able to cast Invisibility once per day.

*Spell neutralize posion is memorized after bearer reaches 9th level