Please do not let your children watch this series. Yes, it has monkeys, which is adorable, but most of those monkeys die except for one who becomes a trained killer. In the original comic, Hit-Monkey's origin story is as violent as the rest of the series. A human assassin running for his life passes out in the snow and is rescued by a group of Japanese macaques. When he comes to, he is welcomed into their family by all but one monkey.

Because the human assassin is still being hunted, he continues to train on his own while hiding out with the macaques. The one wary monkey watches the training while studying his moves. Unfortunately, the rest of his clan isn't as impressed with his newfound skills, and the monkey is banished from his tribe.

While searching for a new home, the monkey sees the men hunting the human assassin on their way to kill him. Before the monkey can warn his clan, they are brutally murdered, along with the assassin. Grief-stricken and filled with rage, the monkey picks up a gun and shoots all of the men who killed the human and his family. To avenge them all, the monkey vows to hunt down all of the world's assassins. It only gets worse from here! This is definitely not for children.