Other Worldly. The yitsan is also known as "treasure bane" and "intruder within". Unwary sailors bring the eggs aboard ship in newfound treasure hoards. Making a rare but dangerous foe for those who take to spelljamming.

Yitsan measure around 10' in height. They are humanoid, with 8' tails. Their skin is a fine mesh of grey-green scales. Yitsan have long claws on their four-fingered hands and toes, and their mouths have three sets of sharp teeth. Perhaps their most unusual characteristic is their lack of eyes. An odor of salt hangs about them.

If the yitsan have a language, it has yet to be discovered. They frequently utter hisses, shrieks, roars, and growls.

Brutal Efficiency. Fighting is what the yitsan does best. Its four sets of long claws. The yitsan can use the claws on its two feet just as easy as the claws on its hands. The only ways it can use all four claws at once is atop a victim, or while trampling underfoot.

The yitsan begins melee using its tail, with its many razor-sharp projections. The tail can strike up to three opponents in a closely-spaced line. Yitsan try to knock it's prey prone with their tail sweeps. The yitsan tries to trample a prone victim with all four sets of claws.

The tail can also wrap around a creature of size Medium or smaller. A yitsan's tail can constrict it's prey, cutting it with the tail's razor edges. The yitsan can attack other victims with its claws while constricting with its tail. 

The yitsan has three rows of sharp teeth. Once its jaws get hold of someone, they continue to grind until the victim either can manage to escape or is killed.

Faceless Hunters. Due to their blindness, yitsan are immune to illusions and any spell that requires the target to see. However, a yitsan's senses of hearing, taste, and smell are inhumanly acute. They locate opponents in a 50' radius by their breathing or their scent (80% chance). Like snakes, the yitsan use their tongues to taste the air. Casting a silence spell on a yitsan gives it only a 25% chance of detecting an opponent. Yitsan have no organization. Each beast is out for itself. Most encounters with yitsan are with young, since adults avoid large groups of humans in favor of less intelligent prey. Yet oddly they hunt in packs, typically of up to 4 yitsan.

Intrusive treasure. A yitsan reproduces by laying a group of 1d4 eggs. These eggs are 1" wide golden disks. To the casual observer, a yitsan egg looks like a gold piece, except that it is featureless.

When the egg hatches, the newborn yitsan resembles a tiny (1") green lizard. It crawls into a cozy crack in a ship's bulkhead and eats bugs, mice, wood, and cloth. The lizard grows to 60" in two weeks, trusting to its chameleon-like hide to remain unnoticed. Sailors may notice small nibble marks in their clothing or wood implements; there is a 1% chance per sailor to notice this per day.

After the lizard reaches a foot in length, it undergoes rapid and painful metabolic changes, maturing in two hours. This frantic growth spurt drains much energy and leaves the adult yitsan ravenously hungry. The yitsan always seeks a private place to mature, for it is helpless during the transformation.

An adult yitsan lays eggs once it has eaten its first meal. Once again it seeks a stash of coins, perhaps even returning to its spawning hoard.

Unknown Origins. The yitsan is a predator of unknown origin. Some elven scholars guess that the yitsan is an orcish biological weapon left over from the Unhuman Wars that somehow escaped into civilized space.