In lipsa de alt context, si presupunand ca nu e vorba de un joc de calculator sau desene animate...

Ninja este asasinul invizibil.
Unul din principiile de baza ale luptatorilor ninja este ascunderea, camuflarea (uniforme speciale de camulflare, pozitii si tehnici speciale de camuflare).

"Moving in shadows requires that a path be selected from one place of concealment to another, crossing any exposed areas quickly and quietly. Standing in darkness requires great patience
and controlled breathing. The best place inside a room is the nearest corner behind the door. Select a shadow to be used and advance silently to it. Assume a posture which conforms
to the shape of the shadow and remain within it. Practice shallow breathing. To become invisible, Ninjitsu employs the Nine Steps of Kuji Ashi."

"Cloaked in darkness and secrecy, the Ghost-Soldiers of the Invisible Fist struck fear into the hearts of their enemies and wreaked havoc on those who incurred their wrath. The principles of these occult methods have not changed and apply even today."