Kunai and Shuriken

Kunai are knives that are chiefly used by shadow warrior. Derived from basic tools, a ranking samurai wouldn't be caught dead witch such an item. It still proves remarkably effective, especially against unarmored enemies.
Shuriken are much smaller throwing knives, and far less efficient at kiling. Poisining the edges is a possibility, but most shadow warriors refuse to use it due to the high risk of poisoning themselves. More often than not, these weapons are used to slow down enemies, not kill them. In a sense, they're glorified caltrops.

5E D&D Rules

• Kunai = Dagger
• Shuriken = Cost: 1 gp (for five), 1 piercing, 1 lbs (for five), thrown, special

Shuriken Special

Shuriken may not be used for melee attacks. If a creature's shuriken have been poisoned, that creature must pass a DC 12 sleight of hand check or recieve damage and all other affects from the poison. The creature may still attack with the shuriken if poisoned this way.

Feats

• Falling Stars: You have become a master of throwing shuriken. You may throw three shuriken in one attack, dealing 1+1d4 piercing damage. Any poison applied to the shuriken is only applied to a struck creature once. Additionally, you must only pass the shuriken saving throw one time to avoid being poisoned.