Pekkle

Pekkle are mischievous shapeshifter spirits from Sakkaku. They are able to take an androgynous human appearance, mimicking the appearance of human beings from infancy up to young adult age, and settle into society with ease. Even if pekkle aren't considered to be evil, they like to play most vicious practical jokes. Using their ability they sometimes steal a human child from the crib and take his place for months, or even years, only to unexpectedly reveal the delusion, rejoicing in the misery of their parents. (Creatures of Rokugan, Third Edition, page 157)

Pekkle no Oni
After his fall, Fu Leng trapped and corrupted many pekkle after his fall. Tainted pekkle are called pekkle no oni, even if they are not actually oni. Their shapeshifting nature makes their Taint very difficult to detect, making of them perfect spies. The only reliable way to detect them is to spill their blood, which is thin and black. (CoR3E, p. 157)

Enemity
Pure pekkle have a mortal hate for their tainted cousins, are able to detect them from a mile away. A pekkle will always attack a pekkle no oni on sight and fight to the death. (CoR3E, p. 157)

Feeding
Pekkle no Oni feeds on the water found in living people. It has a long tongue that it uses to draw all the water out of those it catches sleeping. The victims are found dry and crumbling if they are found at all.