Who is more deadlier a ninja or a samurai?

In the right hands both were incredibly deadly. I'd give the "edge" to the katana, as a broad sWord, while powerful, takes longer to reverse direction.

A katana and/or wakizashi in the hands of a trained samurai could gut and filet you in seconds. Being the lighter weapon, a katana is easier to reverse direction, engage multiple thrusts, and are incredibly sharp.

Samurai sWords are seen by many as the greatest sWords ever made, mostly due to their unique construction, deadly curved blade, incredible sharpness, and high level of training that the samurai received.