Kunai

A staple long-range dagger-like weapon used by Ninja, the Kunai is traditionally a triangular throwing dart that can be modified to suit different purposes.

Ninja Gaiden
Kunai with small timed explosives attached to them. The wielder throws the kunai, at which point the kunai is imbedded in the target and explodes a few seconds later. Kunai with small timed explosives attached to them. Similar to Ryu's varient however these kunai also possess a flower that spins when caught by the wind, creating a destracting sound.
 * Incendiary Shuriken (Ryu):
 * Incendiary Shuriken (Ayane):
 * Kunai with scrolls:

As Ryu traverses from area to area in Ninja Gaiden a kunai with a purple flower attached will be thrown by Ayane into Ryu's vicinity on a wall or on the floor. The kunai will have a folded-up scroll inside the dagger and will usually offer advice, tips, or even a foreshadowing of events to come.