Stickman

Stickmen are actually ninjas in disguise. Also, they're plotting to kill us all.

Evidence

 * Stickman backwards is Namkcits. Ninjas and Namkcits begin with N. Also, ninjas wear a black outfit, and so do some Stickmen. Also, stickmen can dissapear, like Ninjas.
 * Stickmen like chocolate. Ninjas like chocolate too.