From MMB:

1. Kill the mamba and take the mamba fang it drops
2. Go to Master Smith Martok in Khaz and "ask martok mamba fang"
3. Go to gypsy woman in the misty valley and "ask woman fangblade materials"
4. Get a bloodstained shortsword, shadow cloak, 4 obsidian stones, 3 diamonds, and 2 rubies.
5. Go back to Master Smith Martok and "ask martok create fangblade"

From MudCentral:

***Goto Master Smith Martok

ask martok mamba fang

Martok's muscled arm pauses midstrike holding the enourmous hammer

he weilds as though it were as light as a feather. Slowly his gaze turns

to you and the fire in his eyes no longer comes from the embers of the

forge. His shoulders quiver with contained fury as he strides forward

and slams his fist down upon the counter before you.

"A tooth, ye wish me t'make a weapon outta some beasts tooth?!?!

I be a master smith, mine life devoted to working metal in fire.....

I am no trinket maker. Show me what be so special about this item and

ye may be able t' walk outta here with a least one leg unbroken."

Slowly you reach into your pack and begin bring out the snake's large

fang. Before you can have a chance to catch your breath the fang flies

from your grasp. The Master Smith snatches his hand away from the

counter at the last possible second as the fang embeds itself more then

a foot into the wood, spliters flying into the air. A wide grin spreads

across Martok's face as he stares at the tooth quivering in the wood

before him.

"Well she could certainly be a deadly weapon. Ye best ask the ole

witch and her ponies outside town what materials be needed in the

contruction of this fangblade. Return to me with ALL the materials

she suggest and I shall create thee a powerful weapon.

***Goto the Old Gypsy Woman

ask old fangblade materials

"Tis a powerful charm ye hold there yes it tis. Aggie knows just whatcha

need to make er into a weapon, yes she does. Ta start ye off yull need

the small sword so battle worn ye can nary wash de blood ofen it. Next

gems, two rubies for the fire of the serpents blood, four obsidian stones

black as night and three diamonds ta have strength to hold it all tegether.

Last but most important is a cloak of shadows to protect ye for the

bloodlust of the weapon itself. These will help'n ya bind the fang to

a weapon but ye never will be able ta fully control it."

Get the following

Bloodstained shortsword

Shadow Cloak

Two Rubies

Three Diamonds

Four Obsidian Stones

And the fang of course

***Return to Master Smith Martok

ask martok create fangblade

Martok looks at you grinning:

"Do ye have all the material? Lay them out here on the counter."

Clang

.

.

.

Clang

.

.

.

Clang

.

.

.

Clang

.

.

.

Done.

Fangblade Description:

Made from the tooth of a giant viper and crafted by a master weaponsmith, few weapons are the equal to its elegance and deadliness. Bone white with a jewel encrusted pommel it seems as though it has a mind of its own and helps to guide its wielder to draw blood.