Two story questions (SPOILERS)

I saw this film at the Montreal Fantasia festival but I unfortunately didn't stay for the the Q and A with the director at the end. I was wondering if perhaps the following questions were asked and answered. If not, perhaps those who saw the movie have their own theories. Without further ado:


1) How did Choemon (a samurai) know that Denzo was a ninja? It seemed so out of the blue that the audience laughed.

2) Why did the creatures leave so suddenly at the end?


Thank you for your time and answers.