Juukugou wasn't in many episodes so this should be short. He's pure jinzonigen. He was not built from any human construct and by the looks of him, you'd see that he bears little human resemblence. He does have require an energy source. Normal things like walking here and there don't require much, but fighting all out does tend to drain him. That's why Gero contructed him with a little red circle on his hands. If that red circle touches anyone, he can absorb energy through it and it's converted into whatever power supply he may run off of. He can also use it to absorb ki blasts.

Juukugou was built as a protector and servant of sorts for Dr. Gero. Before Gero human form died, Juukugou was the one that transplanted Gero's brain into his new jinzonigen body. On May 12, XXXX two jinzonigen attacked a small island 9 kilometers south of the capital. Those two were Juukugou and Nijugou (The new and improbed Gero).

Note: This is speculation: In Mirai Trunks timeline, the jinzonigen destroyed the island city, however, the Z Senshi interveened and destroyed Juukugou. Nijugou escaped to his labratory and activated Juunanangou and Juuhachigou. And you know the rest.

In the main timeline, the Z Senshi was waitting for the two jinzonigen. However, since they are not alive, they have no ki to sense. When they do eventually find them, they leave to a new locale because of the innocents (well... not many survivors were left...). There SSJ Gokou and Juukugou battled out. Gokou was winning, however, the stress from going Super Saiyajin hastened his heart disease in the middle of battle. Juukugou soon had the advantage and nearly killed him.

However, a certain Saiyajin prince stepped in, and had a rather big secret. SSJ Vejita trounced Juukugou with little effort. Vejita played some little cat and mouse with him. However, after Vejita ripped off Juukugou's hands, Juukugou tried to run for hills, and then Vejita used his new attack: Super Vejita's Big Bang Attack. Big blast followed by a big boom. End result: Pieces of what used to be Juukugou.