Sleep Arrows

The purple sleep arrows are specifically made by the ranger Tseramed in  Ultima VII.

Description
Besides a modest increase in damage, the tip is made from the stingers of giant bees, giving the  arrow the ability to put the target to sleep. Despite this useful effect however, they are rare, since only Tseramed makes them. He will give the Avatar some for free in Ultima VII.

Tseramed Arrows
In  Ultima VII, sleep arrows are only made by Tseramed, and hardly ever found anywhere else.

To get Tseramed to make more, the avatar must fulfill two conditions first: The avatar can then ask him about bees, then about arrows. Then answer yes, and Tseramed will make one arrow for each Bee Stinger the party has.
 * They must speak with Tseramed while a living Giant Bee is nearby, which will change his introductory lines.
 * No party member must already have a single one of these arrows.

Effectiveness of the Weapon

 * Tseramed's Arrows add +1 to the weapon's basic points of damage.

King's Savior Sleep Arrows
In  Ultima VII Part Two, sleep arrows are created by applying king's savior to any plain arrows. This will create an arrow that is capable of putting any creature to sleep, and is specifically needed to kill Draygan.

Effectiveness of the Weapon

 * Sleep Arrows in Serpent Isle also have +1 damage, but that is negated since they are flagged to deal no damage. They are also flagged to always hit.

Trivia

 * The arrows made by Tseramed only appear in Ultima VII.