(I like how you used the ninja's element to her advantage.)
"master," a voice boomed, "The water ninja went back to the dojo."
"Whalzter, you idiot, of course he did!" The commander of the dark samurai was NOT in a good mood. "We will have to sneak there by night and attack, when we will have the upper hand. with two ninja wounded and all three still mourning, it will be a quick and merciless slaughter."
"yes commander, I don't mean to question you, but what if there are any shadow ninja there?"
The commander turned and grinned menacingly at Whalzter. "There are no Shadow ninja left."
"What about that old man? the father of that one cute girl..." Whalzter's voice trailed off as he suddenly stopped and became all woozy-woozy.
"HE IS DEAD! by my own hand! of course, the girl probably never figured it out, given the poison I gave him to -er, made him drink one night. there is no way she could've figured out about her father's secrets and the art of the shadow ninja. so now, as it becomes late, we have no worries about a shadow ninja just hopping out of the shadows without us knowing and killing us."