Created by Dr. Gero, Juurokugou was a failure. He was built long ago, supposedly during the Freezer Saga (sometime when Gokou was not on Earth.). However, Gero believed he was flawed and de-activated him for good. However, after Juuhachigou and Juunanagou was re-activated, they killed Nijugou (Gero, in his jinzonigen form) activated Juurokugou. For a period, no one knows why Gero considered him flawed. But there were several little well-placed hints as to what Gero believed "flawed" meant (as in, not the perfect begin to kill Son Gokou).

Juurokugou isn't exactly the type to throw a housewarming party. He doesn't want to get involved with anyone or anything, he only wants to kill Son Gokou because of Gero's programming. He is very cold, and keeps to himself. We slowly begin to see that Juurokugou does not share the morals of his siblings and wants nothing to do with killing people for fun. He believes that the Earth is beautiful and is home to many cute and cuddly creatures, and he would not like to harm it.

During the Cell Saga, Juurokugou fights with Cell, however, Cell is too powerful and blows off part of Juurokugou's head (Ouchies). He is repaired by Bulma and Dr. Briefs, partly because he is big and strong and also wants to kill Cell, but also because the Briefs' want to see Gero's amazing technology. They remove the self-destruct unit in him, but forget to tell him that until it's too late.

When the Cell Jr.'s are whoopin' ass on the Z Senshi, [the head of] Juurokugou gives Gohan some very valuable advice and is partly the reason why the Earth wasn't destroyed by Cell. He told Gohan that it's okay to fight for what you believe in, to fight for what is right. And to protect the beautiful world that is the earth. Then Cell smashes Juurokugou's head into pieces and Gohan blasts in SSJ2.

Juurokugou was a cool character, unforetunately, he had to die.