Blowpipe

The blowpipe was a weapon that was used by Assassins such as Edward Kenway and French- Aveline de Grandpré. First belonging to the Assassin François Mackandal, the blowpipe was given to Aveline by her Mentor, Agaté.

Used as a silent and deadly weapon, the blowpipe functioned in a similar way to poison darts. Aveline possessed two different types of ammunition for the blowpipe, the first would kill quickly, while the other would have caused a slower and more dramatic death.

Trivia
Assassin's Creed III: Liberation
 * The "Deadly Haystack" achievement could be earned by killing 50 enemies from a haystack using the blowpipe.
 * The "Predator" achievement could be earned by killing an enemy with the blowpipe from a tree whilst using Eagle Vision.

Reference

 * Assassin's Creed III: Liberation